Sebastian Vettel and Kevin Magnussen are squabbling out on track, the Red Bull driver waiving his hand in frustrating as Dane Magnussen appeared to be dawdling on the racing line.

Problems for Jenson Button, the Briton's car is up on the jacks and mechanics are working underneath. That looks like it could be a long delay for the Briton, who has only managed eight laps so far today.

According to BBC co-commentator Tony Dodgins, McLaren say the reason why Kevin Magnussen has the new front wing and Jenson Button doesn't is because Button got to run the last update, which was at Suzuka.

The Mercedes are back out on track, with Lewis Hamilton ramping up the pace and reclaiming top spot with an impressive 1:43.799, four tenths quicker than his team-mate Nico Rosberg can manage.

Ben Edwards
BBC F1 commentator in Abu Dhabi

"Will Stevens has only done the one lap so far, but Kamui Kobayashi has done seven laps and is back out again in the other Caterham car."

Sebastian Vettel, who has won this race in three of the five years it has been held, pops up to third, but the Red Bull driver is still 1.135 seconds off the pace.

Lee McKenzie
BBC F1 pit-lane reporter

"Valtteri Bottas is definitely not going back out in this session. Williams are trying a different cooling configuration and something has gone seriously wrong. The floor is off Bottas's car and they're also taking a good look at Felipe Massa's as well."

We've got more Williams news for you and it's not of the good variety if you're a Valtteri Bottas fan...

What's Red Bull boss Christian Horner's moment of the season?

"We are the only team to beat Mercedes this year so those have been highlights but to have fought our way back and finish second is our biggest achievement this year," he says.

Adam Parker:, external Best part of the season has got to be Fernando Alonso and Sebastian Vettel racing hard at Silverstone! It shows how to race wheel to wheel.

Mathias Zaranyika:, external My fav moment of the season has to be Daniel Ricciardo overtaking two former world champions Hamilton & Alonso at Monza.

Dave Wight:, external Buttons eyes were priceless during the drivers conference as Rosberg asks Hamilton to "drive cleanly".

Allan McNish
BBC Radio 5 live analyst in Abu Dhabi

"There's been no new parts added for this weekend, so they're wondering why - at the same point give or take - the cars have suffered exactly the same issue. Where the engine cover meets the sidepod, pressure has built up and it has popped up.

"There's a bit of head scratching going on down here until they get to the root of the problem."

Williams had a bit of a nightmare earlier in this session when bodywork issues on both Felipe Massa and Valtteri Bottas' cars. Allan McNish has more...

Mercedes:, external A lot of polishing going on in the garage here on both cars! Need to look tip top for the showdown.

Image source, SNTV

Talking of Thursday's pre-event news conference, there was also a tense moment when Jenson Button's eyes lit up when Nico Rosberg said Mercedes team-mate Lewis Hamilton "can do something to keep it clean and that's drive cleanly himself. It's not like he can't do anything". Watch it here.

Andrew Benson
Chief F1 writer in Abu Dhabi

Image source, AP

"There was an amusing moment in the pre-event news conference on Thursday when Fernando Alonso, who was sitting next to Jenson Button, was asked whether would he choose Button as his team-mate next year at McLaren if he had the option to do so.

"Button turned and faced Alonso, big grin on his face, returned by the Spaniard. 'Take your time,' Button said, putting his arm around his rival. 'I don't know where I will be,' said Alonso, smiling broadly and fibbing just as much. 'So'."

Ally Cairns:, external Best moment of season was Bahrain GP, Lewis and Nico wheel to wheel pedal to the metal action for the whole race, exquisite!

Karl Southwood:, external Best moment of the season. When Caterham got rid of that awful nose cone.

Andrew Avramenko:, external Moment of the season: when Rosberg took out Hamilton at Spa, it changed the season around (Thurs conference showed it still rankles!)

The track has gone quiet as the teams have had to hand back the extra set of soft tyres they're given for the first 30 minutes of this session.

Image source, Force India

Force India:, external Welcome to the Sahara Force India villa. They look after us well in Abu Dhabi.

Andrew Benson
Chief F1 writer in Abu Dhabi

Image source, Getty Images

"Most racing drivers have a predictable response to any question about whether people are deserving champions or not, trotting out the line that whoever scores the most deserves the title. It's a very pertinent question at the end of a season in which one of the title contenders has won twice as many races as the other, and has three times come back from about a victory's worth of points down because of car problems.

"And Sergio Perez was unusually outspoken about it. 'Lewis has been really unlucky for a couple of races,' he said. 'He really lost a lot of ground. If he wins he will be a great champion. But on the other hand, Nico has been consistent and always there. Whoever wins will deserve to win and will be a great ambassador for the sport. But I think Lewis should get the championship'."

McLaren:, external Neither driver hugely happy with the balance during that run. We'll have a little tweak before we head out again.