05:33 Good morning from sunny Bahrain and welcome to AUTOSPORT's live coverage of the second pre-season Formula 1 test.

Starting today, the teams have just another eight days of proper testing before the 2014 season kicks off, and the majority of them have some catching up to do mileage-wise after a tricky first test at Jerez thanks to the new regulations.

05:37 Much of the attention is likely to focus on Lotus today, as its E22 is scheduled to make its public debut.

The Enstrone-squad's fellow-Renault runners - most notably reigning world champion Red Bull - will also be in the spotlight after the French manufacturer's Jerez struggles.

Lotus managed to reach its maximum mileage limit during some promotional running at Jerez last weekend, suggesting that it may not be suffering from the same gremlins that struck the other Renault teams.

Red Bull design guru Adrian Newey offered a few clues that might explain that, telling AUTOSPORT earlier this week that his RB10 was hindered by rear-end packaging problems at the first test.

05:44 For the first time in 2014 all 11 teams are scheduled to be in action together today. Here's the full driver line-up:

Red Bull – Sebastian Vettel
Mercedes – Lewis Hamilton
Ferrari – Fernando Alonso
Lotus – Romain Grosjean
McLaren – Kevin Magnussen
Force India – Nico Hulkenberg
Sauber – Adrian Sutil
Toro Rosso – Daniil Kvyat
Williams - Felipe Massa
Caterham – Robin Frijns
Marussia – Jules Bianchi

05:50 This test also marks former Lotus team boss Eric Boullier's first paddock appearance since joining McLaren as racing director.

The Frenchman has already tweeted that he is "back in business!" this morning with a picture from the Bahrain International Airport.

05:52 With a little under 10 minutes to go before testing starts, the current air temperature at the circuit is 16.7C, and track temperature is 28.9C.

05:58 Our F1 Editor @eddstrawF1 is in the pits awaiting the start of the session, and he's already spotted "lots of activity" going on behind the screens that are up at the front of the Red Bull garage.

06:01 Red Bull might get a little bit of peace first thing this morning as the majority of the attention will be focused a few garages along at Lotus, where a crowd is already starting to gather in anticipation of the E22 emerging in public for the first time.

06:02 The screens are up at Lotus, but Edd Straw reports from the pits that the mechanics appear to be making a bit of room for what will hopefully be a prompt roll-out of the car.

06:03 Another good sign from the pits - the E22 has fired up in the garage.

06:06 EDD STRAW is part of the scrum forming in the Lotus pits, and like most he has his camera at the ready looking for a first public glimpse of the E22's unique nose configuration.

06:09 If you want to know more about 'that' nose and the team's theory behind it, here's AUTOSPORT tech expert CRAIG SCARBOROUGH's explanation of the idea:

Lotus's twin-tusk theory explained

06:11 The start of today's test has been delayed.

06:13 It would appear that behind all those screens, Lotus is ready to go with its new car:

@Lotus_F1Team: "Well, we're ready to go out. Doesn't seem like the track is open yet..."

06:15 From the pits, EDD STRAW reports that a course car has just headed out on track.

06:16 As it stands, it doesn't appear that this delay is going to eat into the track time for today. The countdown clock hasn't started, so it is firmly stuck on eight hours to go.

06:18 The always-active Lotus Twitter account is claiming that we currently have insufficient marshals for the session to start. Another theory offered up by circuit staff was a one-word answer: "Teams..."

06:21 Ferrari clearly isn't expecting a big delay here. Fernando Alonso is sat in the F14 T and ready to go.

06:27 Alonso isn't the only one. Lotus has Romain Grosjean strapped into the E22.

06:30 The course car is back from its circuit inspection and we have a green flag. As promised, the Lotus is the first car to head out.

06:32 Grosjean has been joined on track by Hulkenberg, Magnussen, Hamilton, Sutil and Alonso, showing that plenty of teams were keen to get going this morning.

06:32 That didn't last long, we've already got a stoppage.

06:33 Stay calm, Lotus (or Renault) fans, it wasn't the Lotus that caused the red flag. Grosjean is back in the pits.

06:34 The timing screens are suggesting that Alonso has stopped in the first half of the lap. All the other cars that left the pits when we went green have returned.

06:36 Short stoppage. The track is open again.

06:37 No one is quite so eager to take to the track this time, but Robin Frijns breaks the silence in the Caterham.

06:38 Over in the pits, EDD STRAW did catch a shot of Grosjean in the Lotus when he headed out earlier.

06:39 Here's more about the Lotus E22's emergence and the team's troubled winter:

Lotus E22 makes public debut

06:39 As Frijns returns at the end of that same lap, Sauber claims it won't be long before Sutil is sent back out having used that first tour to complete a radio check.

06:40 Temperatures are still climbing here:

Air: 17.8C
Track: 33.3C

06:44 With nothing on track, here's some meaningless information: Hulkenberg's Force India went fastest through the middle sector when a handful of the cars went out for those sighting laps earlier.

06:45 Fernando Alonso, of course, didn't make it quite that far in the Ferrari earlier. On that subject, EDD STRAW has made an observation from the pits...

06:46 Snap-happy Straw has spotted a fluid trail in the pitlane that was left by "smokey Alonso" when he headed out earlier.

06:47 Out on track, Lewis Hamilton is the first driver to cross the start/finish line and move onto a second lap.

06:49 Hamilton doesn't set a time - he's back in the pits after just a two-lap run.

06:51 More silver on the track as Kevin Magnussen takes the McLaren out.

It's no surprise to see the teams taking a cautious start here. Even the mild air temperature of 18C is a big step up from what we had at Jerez, so everyone will want to be careful from a reliability point of view as they get up to speed.

06:52 On the subject of McLaren, EDD STRAW reports that the MP4-29 is once again running the eye-catching suspension 'blockers' that created so much interest at the first test.

GARY ANDERSON explains McLaren's blocker idea

06:54 If you want to stare in awe at the Lotus E22 and its unique front, we've added an initial set of high-res pictures to our testing gallery, with plenty more to come.

Bahrain F1 test in pictures

06:55 No sign of an imminent run for Red Bull at the moment. The garage doors are shut as work continues on the RB10.

On track, Sutil's Sauber is the first car to log a time of any sort - a 1m48.710s

06:58 We're giving EDD STRAW a workout in the pits at the moment, and he's found out a bit more info regarding the 30-minute delay we had this morning:

"The word in the pitlane is that some marshals were not in position at the allotted time. Officials then wanted to check the circuit and work out if any more were missing and if so, how many.

"Team personnel were generally disgruntled about the delay."

06:58 Sutil is still going on track, and he has lowered his best lap to a 1m44.335s.

07:01 Alonso takes the Ferrari back out after causing that earlier red flag.

The F14 T has a big aero sensor mounted in front of the left-rear wheel, and this time there is no sign of the smoke plume that trailed the car when it left the pits for the first time earlier.

07:04 After most teams used Jerez as little more than a shakedown to get their heads around the new rules package, we can expect to see a lot of developments appearing on the cars at the next two tests as everybody ramps up for the Australian GP.

Sauber was one of the teams to promise a big aero upgrade for this test, and the C33 - the only car to have set a time so far this morning - has indeed emerged with a series of updates.

07:07 Felipe Massa has taken the Williams out for the first time today. As usual, a radio check is the first item on the agenda.

Sutil has pitted, having taken his lap count up to nine for the day, while Hulkenberg has just returned from another installation lap.

07:11 With Sutil the only driver to have set a lap time, EDD STRAW noticed something on the Sauber during that short run. The car appeared to have cameras mounted to it, recording front wing behaviour and rear suspension travel.

07:13 Drivers not in action today are in spectator mode, including Max Chilton, who tweets this picture of his chilled-out legs, and fuels the anger of those who claim 2014-spec F1 is too quiet:

"Jules is in the car today & I will be in tomorrow & Friday. Still odd sitting on the pit wall with no ear protection."

07:16 AUTOSPORT's JONATHAN NOBLE recently argued that noise didn't matter in F1 based on his experience of the Jerez test. He's on half-term holiday duties this week so is probably pining for the quiet of a 2014 F1 car.

07:16 Force India reports that at the top of Nico Hulkenberg's to-do list this morning is in- and out-laps and 'constant speed' aero work.

07:18 Lewis Hamilton's first timed lap of the day takes the Mercedes to the top of the timesheets with a 1m41.750s.

07:20 As Hamilton improves again, his current 1m41s are around five seconds shy of last year's Bahrain GP fastest lap.

07:22 There's work going on behind screens at Williams, where Felipe Massa is out the front of the garage chatting to team-mate Valtteri Bottas.

07:23 According to EDD STRAW, the engine cover has been taken off the Williams and he can see "feverish activity". He's also heard that the issue could have involved the power cutting out when Massa took to the track earlier.

07:26 Unlike on GP weekends, the teams are free to block sight/access to their garages from prying eyes.

While Williams gets busy with the FW36 behind those screens, team personnel are out the front of the garage extending an 'exclusion zone' to prevent anyone from getting a closer look.

The tactic has worked, as it has convinced EDD STRAW to return to the media centre.

07:28 Quick update on Alonso causing a red flag earlier: The two-time world champion did manage to get the car back under its own steam, but it was a couple of minutes after the session had been stopped.

07:31 Nothing on track at the moment, and it's still only Hamilton and Sutil who have logged a time today.

Of note, we have only seen nine of the 11 cars so far this morning.

No sign of Red Bull or Toro Rosso yet...

07:34 We've had just over an hour of running, and here's how the lap count looks so far:

Hamilton (Mercedes) 11 laps
Sutil (Sauber) 9 laps
Hulkenberg (Force India) 4 laps
Alonso (Ferrari) 4 laps
Magnussen (McLaren) 3 laps
Frijns (Caterham) 2 laps
Bianchi (Marussia) 2 laps
Grosjean (Lotus) 1 lap
Massa (Williams) 1 lap

07:36 Grosjean heads out to add to the Lotus lap count on the team's first public day of running with its new car.

07:39 With the Lotus logging some laptimes, Alonso heads out to join the action.

07:42 Grosjean pits, and Alonso gets himself on the timesheet with a 1m41.667s.

07:44 Alonso caused the first red flag of the morning, having exited the pits with a plume of smoke from his Ferrari.

Problems are inevitable for the 2014 F1 cars at this stage, and the teams are having to go through their teething troubles in the public eye - AUTOSPORT pounced on the pics of the smoking Ferrari as soon as they appeared, and we won't be the only ones.

Our columnist DIETER RENCKEN got readers talking after Jerez when he controversially suggested that F1 should do its testing in private...

07:45 Now Ferrari gets a message from race control saying that the transponder on Alonso's car has stopped working.

07:46 The Ferrari does appear to still be logging times though. Since setting his current best, he has come round in 1m41.8s and 1m43.4s.

07:47 With the "transponder not working" message still flashing for Ferrari's benefit, Alonso shaves a bit more off of his best to set a 1m41.115s.

07:49 The work that Williams didn't want anyone to see in its garage is completed, and Massa is on track for the second time today.

07:49 AUTOSPORT's JONATHAN NOBLE is tipping Williams as a dark horse for 2014. Here's why:

Does Williams hold the aces?

07:53 Massa and Alonso both return to the pits. Massa completed another installation lap, while Alonso has taken his 'laps completed' tally up to 12.

07:54 Alonso quickly returns to the track. He's done more laps than any other driver so far.

07:57 Alonso is back in the pits and into the garage this time, but Ferrari power is still represented on-track thanks to Adrian Sutil's Sauber, which has now clocked 10 laps.

07:57 Latest updates to our testing gallery include that smoking Ferrari, plenty of Lotus E22 close-ups and the usual array of ungainly-looking sensor equipment:

Bahrain F1 test in pictures

08:02 Massa returns to the track in the Williams FW36. Sutil has now completed 14 laps in the Sauber.

08:09 Caterham reserve Robin Frijns clocks a 1m47.529s lap to go fifth fastest. This is his first flying lap of pre-season testing having failed to set a time at Jerez.

08:10 Still no sign of Red Bull leaving the garage today. The champion team has so far completed fewer miles than anyone else in 2014.

It certainly has the pedigree to recover from that, but it's a worrying situation with such a big rule change and so little testing allowed.

And while all the Renault teams have had issues, Adrian Newey admitted to AUTOSPORT this week that the way the V6 is packaged in the car was an equally big factor (though he did mention Renault's "particularly large" cooling needs too...)

08:10 It's worth remembering that not all Newey's designs have been overwhelming successes (just the majority of them...)

When Newey got it wrong

08:11 Caterham reports that Frijns has been sent out for his first "longer run" of the day, so he'll be looking to clock up the mileage for his new team.

08:16 Frijns back into the pits now after a total of seven laps in the Caterham. Not exactly a long run, but almost matches the 10 in total he managed at Jerez...

The Dutchman's best lap puts him just 0.4s shy of Grosjean's Lotus, which has just headed back out.

08:18 Hamilton's Mercedes is back out and the 2008 world champion is the first man to crack the 1m39s.

08:21 AUTOSPORT F1 Editor EDD STRAW: "Renault's progress in Bahrain was always going to be interesting to follow. While Lotus has managed seven laps with the new E22 and the Caterham has also been on track, both Red Bull and Scuderia Toro Rosso remain inactive.

"Head of track operations Remi Taffin was optimistic when speaking last Friday about the progress made with troubleshooting both the hardware and software problems since the Jerez test and predicted that 'we will get into Bahrain and the first day without all of the issues that we had in the first test, which we now believe are closed'.

"We're only two hours into that first day, so it's too early to draw any conclusions but the fact two of the Renault teams haven't even got out of the garage yet is concerning, particularly for those owned by an Austrian energy drinks giant.

"The bottom line is that we have yet to see a credible, quick laptime from a Renault-engined car with over a third of the available pre-season testing in the history books."

08:31 Hamilton shaves another tenth off his best time. The fastest lap of the day so far is now a 1m39.464s.

08:32 Nico Rosberg is on his way to Bahrain today as he takes over from Hamilton at Mercedes tomorrow. It's turned out to be a spiritually enlightening journey for Rosberg, as he bumped into the Dalai Lama on the way:

"@dalailama great to meet you in frankfurt! Thx for your time. I finally know what to answer when journos ask me which influential person i would like to have dinner with!"

08:35 Frijns moves up to fourth fastest in the Caterham. His 1m44.337s lap makes him the fastest Renault-powered driver in Bahrain so far.

08:36 McLaren's Kevin Magnussen completes his first flying lap. A 1m41.048s effort puts him second fastest behind Hamilton.

08:37 Magnussen goes fastest of all on his next tour. He's now a tenth quicker than ex-McLaren man Hamilton.

08:38 Magnussen goes quicker again. Now down to a 1m39.266s best and nearly two tenths up on Hamilton.

08:44 Force India returnee Nico Hulkenberg has put himself on the timesheet now. A 1m40.410s effort places him third fastest, behind fellow Mercedes-engined runners Magnussen and Hamilton.

08:44 We've sent EDD STRAW back to the pits, and naturally he made the Red Bull garage his first stop-off point.

He reports that there are signs of life from the world champion outfit, which has opened its garage doors again.

08:46 Magnussen shaves another few hundredths of a second off his benchmark time. He's now 0.230s up on Hamilton, whose Mercedes is back in the pits now.

08:46 Red Bull has just fired its Renault engine up, but it still has the car up on stands so it doesn't appear that we'll be getting a first lap of the day from the RB10 just yet.

08:49 Hulkenberg becomes the third driver to break the 1m40s barrier in his Force India. Still third fastest on 1m39.923s.

08:51 AUTOSPORT's technical expert (and ex-F1 designer) GARY ANDERSON gives an insight into one of the more below-the-radar issues that teams need to get on top of at a test like this:

"Never mind out-and-out performance, this is a very important test to show to yourself that you can run to a time schedule.

"When it comes to a race weekend you need to have the car ready when the pitlane opens, be in a position to optimise the set-up as the day progresses, and if all goes well you park it in the garage at the end of each of the sessions to give the mechanics some time to service the car and get it ready for the next one.

"If a team can achieve this and simulate a race weekend including a race distance then they will go away from Bahrain very happy."

08:52 Magnussen back into the pits now, having clocked 14 laps in the McLaren MP4-29 and lapped consistently in the 1m39s.

08:55 If you're just joining us, here are the headlines from Bahrain so far:

*Lack of marshals delayed the start by 30 minutes
*Alonso's smoking Ferrari caused a red flag early on
*The new Lotus E22 made its public debut
*Red Bull and Toro Rosso have completed no laps so far
*McLaren and Mercedes lead the way

09:03 After spotting a cat making its way across the pitlane to the pitwall, EDD STRAW has got the latest from Red Bull:

"We're still fitting some new parts but hope to be out soon," the team tells him.

09:04 We're two and a half hours into today's Bahrain test. Here's the lap-count so far:

Sutil (Sauber) 30 laps
Hamilton (Mercedes) 23 laps
Frijns (Caterham) 18 laps
Magnussen (McLaren) 14 laps
Hulkenberg (Force India) 14 laps
Alonso (Ferrari) 13 laps
Grosjean (Lotus) 7 laps
Massa (Williams) 3 laps
Bianchi (Marussia) 2 laps

09:11 Naturally, most of the attention on the non-runners is focused on Red Bull, but we are still yet to see its little brother Toro Rosso as well.

The team tells us that it is working to get the car out, but it's not in a position to set an expected time for the STR9 to emerge from the garage.

09:14 More from EDD STRAW on the work going on in the Red Bull garage, part of what the team described on Twitter just now as a "slight delay".

It comes as little surprise to hear that Straw has spotted "work going on around the back" of the RB10. He adds that it "sounds like there might be some cutting or grinding equipment involved".

Sorry, we don't have a cutting or grinding icon...

09:20 As Frijns brings his latest run in the Caterham to an end, the green machine is emphatically leading the way for laps completed by a Renault-powered car.

While Lotus's lack of running (seven laps) is understandable as today is the public debut of the car, the fact that a Renault team is now up to second on today's lap count with 25 certainly suggests that the problems at Red Bull and Toro Rosso are more team-specific than they were at Jerez.

09:24 Hamilton's Mercedes has broken the silence at the track.

09:27 There has been plenty of talk in the paddock this year about how Hamilton - a man not over-keen on being conservative to preserve fuel/tyres/the car - would cope with the new regulations and their emphasis on fuel economy.

But Mercedes co-chief Paddy Lowe recently dismissed any suggestion that 2014 would be a year of radio angst for Hamilton and told reporters they were "overplaying" that angle.

09:29 Alonso joins Hamilton on track, and he's managed a personal best middle sector on his out lap.

09:35 Seems there are still some transponder issues with Alonso's Ferrari, which is not appearing in all the sector times. The Spaniard is currently lapping in the 1m43s which is 2s shy of his best.

09:37 Sutil joins the action, kicking off his run with a practice start at the end of the pits.

09:39 The latest from EDD STRAW in the pits is that Toro Rosso's delays today have been caused by an oil leak.

09:39 Frijns rejoins the fray in his Caterham, so we currently have three cars out on-track in Bahrain.

09:41 We've got our second stoppage of the day.

09:42 It appears to be Sutil in the Sauber (which has completed the most laps today so far) that has not made it back to the pits this time.

09:49 While we wait for the Sauber to be recovered, some significant news from the F1 foothills...

There's a battle brewing on the F1 ladder with the FIA warning against the use of the 'Formula 3' name by series not running to its latest engine regulations, including the British championship.

The latest twist revealed by AUTOSPORT's F3 expert MARCUS SIMMONS is that the annual Masters of F3 at Zandvoort has had to drop the F3 name and will be run for cars from the British and German series this year.

Zandvoort Masters to be run for 'non-F3' cars

Previous Masters winners include current F1 racers Lewis Hamilton, Nico Hulkenberg, Jules Bianchi and Valtteri Bottas.

Even with the profileration of categories these days, F3 still matters. Only four of the current F1 field skipped it, and the 2014 grand prix grid includes seven F3 champions (two from the British series, four from Europe and one Japanese title-winner).

09:50 Back in Bahrain, ex-Lotus chief turned McLaren racing director Eric Boullier has been spotted in the pits in his new grey (silver?) colours.

09:56 The track is clear, and the green flags are out. Hulkenberg and Frijns leave the pits immediately.

10:02 Three cars on track now as Alonso rejoins the action, but it's short-lived because Caterham has brought Frijns back in.

10:06 Caterham is certainly showing it's serious about Frijns.

A day of running at each of the tests so far will mean he has similar mileage to race drivers Kamui Kobayashi and Marcus Ericsson come Melbourne, and there was abundant praise for him at Caterham's pre-season media event, with team boss Tony Fernandes admitting the Dutchman was nearly put straight in a race seat.

10:14 Here's our round-up of the morning's events so far:

Magnussen fastest, Red Bull still in trouble

10:15 As was the case at Jerez, there isn't an official lunch break at Sakhir, so there tends to be an unofficial lull-for-food in the middle of the day when the track goes quiet.

10:19 Red Bull's stereo does not have teething troubles:

"Michael Jackson: "You Got Me Workin' Day & Night And I'll Be Workin' From Sun Up To Midnight", currently playing in the garage. Stay tuned."

10:22 It's not entirely plain-sailing for current pacesetter McLaren, though.

Our snappers spotted this bit of scorched bodywork at the rear of Magnussen's car when it returned to the pits.

10:33 Continuing the 'how do the 2014 F1 cars sound?' debate, the AUTOSPORT team's latest conclusion is that it's a little bit like the noise of LMP1 cars on the Le Mans start/finish straight.

10:38 Just reached the 50-picture mark in our high-res test gallery from this morning, which now includes all the angles of the Lotus E22's tusks that you could wish for.

Bahrain F1 test in pictures

10:41 High-level Red Bull and Renault personnel have been spotted in conference in the paddock.

It may still feel like the winter running has only just started, but at the end of tomorrow's session half of pre-season testing will already be over and the champion team is running out of time to catch up.

10:46 Lots of people in the Sakhir media centre nodding appreciatively at this video Mercedes has just published - a 360-degree onboard lap of Silverstone with its W05 on its filming/shakedown day last month.

10:47 And our photographers bring evidence of the Red Bull/Renault discussions as we still wait for any sign of movement from the champion squad's garage.

Feel free to analyse the frowns.

10:48 But just as we publish that, a breakthrough in the pitlane as Vettel finally leaves the garage and heads out on track.

There's still just over three hours of running to go for the German today.

10:54 To give a sense of how much catching up Red Bull has to do, here's our round-up of the Jerez test last month, showing just how much mileage everyone managed, and Red Bull is firmly at the foot of the pile:

Jerez test results, stats and round-up

10:57 Vettel's installation lap at least means that he and the Red Bull have appeared on the timing screens for today, leaving just Toro Rosso missing.

10:59 The world champion heads back out in the RB10...

11:01 McLaren's Kevin Magnussen is still setting the pace. He's the only man in the 1m38s now, while Force India's Nico Hulkenberg has closed to within a tenth of Lewis Hamilton's Mercedes.

Sauber's Adrian Sutil has jumped Fernando Alonso's Ferrari to go fourth quickest.

11:02 Vettel sets a 'flying' lap, and by that we mean he's registered his first timed lap of the day. It's a 1m45.095s, nearly 7s adrift of Magnussen's pace at the front.

11:04 With a lap time on the board, Vettel returns to the pits. Red Bull has four laps in the bag, while Mercedes, Sauber, Caterham and Ferrari have all surpassed 40 already.

11:06 Vettel's four laps at least means his team now has more miles under its belt today than Williams (3) and Marussia (2).

11:11 Hamilton heads back out. He's second on lap time and laps completed, trailing Magnussen by 0.858s and Sutil by four laps.

11:16 Hamilton leaps back to the top of the times on his 53rd lap of the test. First man into the 1m37s, putting him just a second shy of Vettel's fastest race lap at last year's Bahrain Grand Prix.

11:25 GARY ANDERSON explains the scorching we saw on the rear of the McLaren earlier.

"By regulation, the back of the rear impact structure/rear light has to have its centre at 300mm high.

"With the exhaust pipe mounted on the centre line of the car and the minimum height defined in the regulations at 350mm, this is where most teams would want the exhaust outlet to help the diffuser.

"So it's no wonder that the top of the crash box gets a little scorched. Improved heat shielding will soon fix this, but I wonder if it would pass the rear impact test in this condition?"

11:27 Hamilton, now up to 60 laps for the day, is still pounding round on the same run that started with that pace-setting time.

Since that 1m37.9s effort he has been consistently lapping around 1m40s-1m41s.

11:31 Hamilton's times might have risen slightly, but bringing the fastest time of the day so close to 2013 race pace is one in the eye for those concerned about the speed of the new cars.

The concern that 2014-spec F1 was "too slow" was shared by several drivers after Jerez. Looks like we're moving away from that as teams get to grips with the new-generation machines.

11:34 This is more like it from Hamilton. The Mercedes driver has turned the wick up slightly, stringing together a sequence of 1m40.3s laps and following that up with a 1m39.827s. This is turning into a tidy run.

11:35 Just as we say that, he drops to a 1m44s - his slowest lap of a run that is now into double figures.

11:37 While Hamilton continues to notch up the laps (now 66 for the day), Vettel (with four to his name) heads out to join him in the Red Bull.

11:40 Vettel sets two personal best sector times on his out-lap, and follows that up with a full set of PBs next time around. That gives him a 1m42.3s and moves him above Frijns into P6.

11:41 That lap does at least make the Red Bull the fastest Renault-powered car here today, moving two seconds clear of the times set by Frijns in the Caterham and Grosjean in the Lotus. The German is now back in the pits.

11:45 Hamilton pits at the end of a run that was firmly into the teens in terms of laps completed.

11:48 We've got Magnussen, Hulkenberg and Frijns out on-track now. Hulkenberg is lapping in the 1m40s, Magnussen in the 1m41s, Frijns is... just getting warmed up (1m50s).

11:51 Frijns pits again, leaving Hulkenberg and Magnussen lapping the track. And now Toro Rosso's Daniel Kvyat is venturing out of the pits for his first lap of the day.

11:52 With an installation lap under his belt, Kvyat takes the Toro Rosso back to the pits.

11:54 Hulkenberg back in the pits after a fairly short run. Magnussen still out there lapping consistently in the mid-1m42s now.

12:00 Magnussen's last six laps have all been in the 1m42s, ranging from a 42.1s to a 42.8s.

12:05 For the first time on a run that is now into double figures, Magnussen drops out of the 1m42s with a 1m43.899s.

12:09 Mercedes has confirmed that Hamilton's long-ish run earlier was 18 laps. Meanwhile on track Frijns improves in the Caterham to set a 1m42.900s.

12:12 Hulkenberg goes fastest for Force India with a 1m37.155s. That's 0.7s clear of Hamilton in the Mercedes, and only 0.2s slower than last year's race fastest lap set by Vettel's Red Bull.

12:14 Elsewhere, Vettel is back on track after around 30 minutes spent in the pits, and Magnussen is still going on his long run, with his times seemingly stabilising around 1m43s now.

12:15 Another improvement at the top for Hulkenberg, and his 1m36.953s makes him the first driver to beat the 2013 Bahrain GP fastest lap in a 2014 car.

12:18 Vettel teases with a personal best first sector, but he aborts the lap and returns to the pits with his total for the day finally into double figures.

12:19 Hulkenberg follows up his 2013-conquering effort with a 1m37.1s, making that the third lap on this run that is quicker than anyone else has managed so far today.

12:20 As Hulkenberg pits in the Force India, Hamilton and Mercedes take the opportunity to have the track to themselves.

12:23 Hamilton opens with a 1m38.7s which, considering only three cars have dipped under 1m40s so far today, is a decent start to this run.

He follows it up with a 2m00s lap, so let's see if that was a 'cool-off' before going for another quick one.

12:25 Nope, that lap was on course to be even slower, and Hamilton returns to the pits.

12:32 Kvyat heads out in the Toro Rosso, and this time he has stayed out beyond completing an installation lap. His first time is a 1m44.346s.

12:34 We've got a red flag here. Kvyat and the Sauber of Sutil were the only cars on track.

12:37 Apologies, Magnussen was out there too. But he and Sutil have returned to the pits, so it looks like the Toro Rosso has stopped just after setting its first time of the day.

12:51 This delay is a good chance to bring to your attention a story from Formula 1 support series GP2.

The champion Russian Time team, which took over the iSport operation at the start of 2013, had a bit of a question mark placed over its future earlier this week.

Its operating team withdrew its involvement - a decision that followed its founder dying suddenly earlier this month.

In a twist, iSport management is back involved and will run the team with 2012 GP3 champion Mitch Evans and German Formula 3 runner-up Artem Markelov its drivers:

Evans to Russian Time for GP2

12:55 According to the timing screens, Kvyat stopped in the middle sector of the lap, and his car was brought back to the pits around 10 minutes later.

13:02 The session is alive again, and we have Hulkenberg, Sutil, Alonso, Vettel and Magnussen all on track. That's the most cars we've had on track at once all day.

13:02 Straight out of the box, Hulkenberg sets a new benchmark, trimming almost a tenth of a second off of his previous best.

13:03 He's not the only one improving as we enter the final 90 minutes of running - both Alonso and Vettel have found some time as well.

13:05 Another improvement for Vettel as he gets down to a 1m40.224s, moving him up to P5.

13:07 Vettel is on course to improve again having set two personal best sectors on his current lap, but that effort has been scuppered by another red flag.

13:08 The timing screens seem a little confused as to which sector Vettel is in at the moment, so could it be the Red Bull that has caused this stoppage?

13:08 As Magnussen makes it back to the pits, that means every car has returned except Vettel's...

13:10 The world champion had just set personal bests on his two previous laps, and he was on course to go faster again on the lap that ended up causing the red flag.

13:13 It would appear that the Red Bull has been returned to the pits.

13:14 The lap Vettel was on looks to have been around 2-2.5 seconds down on Hulkenberg's best before the Red Bull stopped. Vettel is currently 3.3s off the pace overall.

13:19 Vettel was not the only driver improving before the stoppage, but rooted in the garage and to the foot of the times was (and remains) Romain Grosjean's Lotus.

Perhaps that's understandable given it's the new car's first public running after missing the Jerez test, but there's little doubting right now is crunch time for the Enstone squad.

The E22 gets special treatment in this week's issue of AUTOSPORT, as we put the team, Grosjean and new team-mate Pastor Maldonado under the microscope.

All that, and more, is available in stores and online from tomorrow.

13:23 Thanks to this morning's 30-minute delay, there's still more than one hour remaining on the clock for today's running. But, as always, that keeps ticking while the red flags are out.

13:27 As a digger drives past the media centre (surely a coincidence), the track is open again. Sutil, Frijns and Hulkenberg head out.

13:31 We're now inside the final hour of running here in Bahrain.

13:33 After the previous red flag period, we had a series of improvements when the track went green again. Four cars have got down to work this time, and Alonso has improved to get within a second (just!) of Hulkenberg's best and take P2.

13:37 Hulkenberg, Magnussen and Sutil are all lapping around 1m41s-1m42s. Alonso is the odd one out - after that quick lap he has dropped his pace considerably, logging a 1m48s and a 1m44s.

13:39 It's been a long time since we've seen the Williams or Marussia on track. But Jules Bianchi is kitted up and ready to take the latter out on track shortly.

Williams, we believe, has been plagued by engine-related issues today.

13:40 Williams and Marussia currently sit at the bottom of the timing screens (having not set a time) and the lap count for the day, with three and two respectively.

13:45 Williams has joined Marussia in returning to the action, as Massa leaves the pits for the first time in hours.

13:46 It's just an installation lap for the Williams, which returns to the pits and still doesn't have a time to its name for today.

13:47 Williams adds on Twitter that its problems today have been down to "a fuel system issue".

13:49 We're into the final hour of day one here in Bahrain. For those who've just joined us, here are today's headlines:

*Hulkenberg beats 2013 fastest race lap to top the times
*Red Bull suffers more woe with its recalcitrant RB10
*The Lotus E22 makes its public debut with Grosjean
*Hamilton and Magnussen set the pace early on

13:49 While we're updating on those that have struggled to log laps today, Marussia's delays were caused by what the team has called "an IT configuration problem".

The team thinks it is now on top of the issue.

13:54 That flurry of post-red flag activity has settled down now, and with 36 minutes remaining Magnussen's McLaren has the track to itself.

13:55 Magnussen pits, so silence falls over the Sakhir circuit for the moment.

13:58 BEN ANDERSON reports that when he last had a wander through the paddock he spotted Lewis Hamilton - having changed out of his race gear - chatting with Mercedes team-mate Nico Rosberg. Does that mean that Hamilton's work is done for the day?

13:59 Frijns takes the Caterham back out as the sun starts to get lower in the sky.

14:04 The Dutchman has found another four tenths, but it's not enough to vault him ahead of Vettel or Sutil.

14:07 While Frijns comes back in, the man to follow him as Formula Renault 3.5 champion - Magnussen - takes the McLaren out.

14:12 Hulkenberg - still quickest today by 0.999s - heads back out. We're into the final 20 minutes now.

14:13 The teams will have to get used to running in Bahrain without a vibrantly sunny backdrop.

While we're not quite running at 2014 race start time, this year will be the first the circuit hosts a night race.

Which also explains the added floodlight representation around the track.

14:14 As Alonso joins the track as well, Force India has a bit of fun and decides not to give anything away about its programme for the rest of the day.

@clubforce: "Back to the track for @NicoHulkenberg - will this be the last run of the day, or is there more on today's programme? 18 mins to find out..."

14:17 Talking of Hulkenberg, he's lapping around 1m40s at the moment.

14:20 Magnussen's latest run has taken him to the top of the lap count for today. He's just surpassed Sutil's mark of 75.

14:22 Less than 10 minutes to go, and we have Hulkenberg, Alonso, Magnussen, Sutil and Frijns on track.

14:29 Frijns improves his best time with just under two minutes left of today's running. He's still seventh on a 1m42.534s.

14:31 The chequered flag is out, bringing the first day of the Bahrain test to a close. Hulkenberg, Sutil and Frijns are still out on track.

14:41 Running is now finished. Here are the best times and number of laps completed by each driver:

1 Hulkenberg (Force India) 11m36.880s (78 laps)
2 Alonso (Ferrari) 1m37.879s (64 laps)
3 Hamilton (Mercedes) 1m37.908s (74 laps)
4 Magnussen (McLaren) 1m38.295s (81 laps)
5 Vettel (Red Bull) 1m40.224s (14 laps)
6 Sutil (Sauber) 1m40.443s (82 laps)
7 Frijns (Caterham) 1m42.534s (68 laps)
8 Kvyat (Toro Rosso) 1m44.346s (5 laps)
9 Grosjean (Lotus) 1m44.832s (8 laps)
10 Massa (Williams) no time (5 laps)
11 Bianchi (Marussia) no time (3 laps)

14:44 That's it for AUTOSPORT Live's coverage of the opening day of testing here in Bahrain.

We'll return at 6am tomorrow morning, so for now stick with AUTOSPORT.com for the best reaction to and analysis of the first of four days of running at the Sakhir circuit.

Hulkenberg fastest as Red Bull hits problems again