All change at the top of the order as Sebastian Vettel does a 1:22.600 on his return to the track before Valtteri Bottas and then Lewis Hamilton lop more than a second off that time. 

Hamilton is now P1 with 1:21.521, 0.023s quicker than his team-mate.

Gavin Fowke: I'm listening from Kingston-Upon-Thames, definitely not exciting!!!   

Just saying: Brian in Bury!!  

Anon: Most of the office in "Sunny" Ruislip paying attention and feeling sorry for Alonso...

Better. The dullest place I listened to F1 was Leigh Delamere services after my car broke down. Top that?

Image source, Getty Images

Speak of the devil, well he's not the devil he's a very nice young man, Max Verstappen has just gone quickest of all with his first timed lap - a 1:22.706.

Ferrari have sorted the issue with Sebastian Vettel's car and the four-time world champion gets back in on the action.

Daniel Ricciardo, currently fifth quickest, is out of his car in the Red Bull garage. There's some work being done to it. 

Max Verstappen is one of just two (three if you count Fernando Alonso) drivers yet to set a time. The other is Daniil Kvyat.

Felipe Massa is F1's Benjamin Button. the 36-year-old has come back from retirement and is driving as well as he ever has and seems to be really enjoying himself as well.

He's currently fourth quickest, a second off Lewis Hamilton's pace after doing a 1:24.618 on mediums.

Kevin Kelly: 3am hello from Arkansas #BBCF1, external only F1 fan in the state!   

Nick T: add Colorado to that list!  

Craig B: Another from Colorado at 2:40 AM.  

Everyone appears to be following the action from exciting places. Anyone listening in from Slough? Oldham?

Jennie Gow
BBC Radio 5 live pit-lane reporter

Ferrari took the bodywork off the rear of the car and had a look around. Sebastian Vettel thought it was a gearbox issue, the team say it was not a gearbox issue at all. 

Image source, .

This is how the timing screen looked just before Lewis Hamilton went quickest.

Image source, .

Can't help but feel this is the only way we'll get to see a smiling Fernando Alonso this weekend...

Mercedes continue to tussle at the top of the timesheet as Lewis Hamilton goes 0.083 seconds quicker than his team-mate to go top with 1:23.531.

Kimi Raikkonen is P3, eight tenths of a second off the pace with Daniel Ricciardo fourth, 1.4s off Hamilton's time.

Everyone is out on the hard tyres, by the way.

Lewis Hamilton briefly leads the way as he does a 1:23.637 but Valtteri Bottas goes 0.023s quicker to reclaim top with an hour to go.

Jennie Gow
BBC Radio 5 live pit-lane reporter

Sebastian Vettel is still in the car so whatever the problem is it won't take long to sort out.

Andrew Benson
Chief F1 writer in Barcelona

Image source, Getty Images

Ferrari have started this season off on the front foot, with two wins for Sebastian Vettel and the championship lead after four races - in fact the German is in the best place he has been after four races since 2011, and we all know what happened that year. The big question, though, is whether Ferrari can address a weakness of the last few years and keep up in the development race. They, too, have some upgrades this weekend, including refined barge boards, a more complex T-wing and a very intricate diffuser edge. 

Vettel said: “It was impossible to have any expectation going into the season because everything was so new. we just tried to build the best car we could and there is no doubt looking at the results we have the right group of people to build a car to win races. But it matters what you keep doing not what you have done. I know we still have the same people and believe they can bring the upgrades we need to keep fighting.” 

There's one driver replacement to mention for first practice and no, it's not Roscoe in the Mercedes. 

Sergey Sirotkin is behind the wheel of the Renault again. He replaced Nico Hulkenberg for FP1 in Russia and is this morning in for Jolyon Palmer.

It's a happy return to Barcelona for Max Verstappen. This is, of course, where he won last year - his first win in Formula 1.

Verstappen is one of four drivers yet to clock a time. At the top of the order is Valtteri Bottas with a 1:25.027. Kimi Raikkonen is P2 with (+0.6).

More problems on the track... and it's not a McLaren. Stoffel Vandoorne is actually tootling around quite contently at the moment.

Instead it is the championship leader who has had a bit of bother. He's had a gearbox issue and has come to a stop at the end of the pitlane.