Day one of pre-season testing - done. Thanks for your company - I've had a blast. Let's do it all over again tomorrow. See you back here at 08:00 GMT. Until then, it's good afternoon from me. See ya!

Force India have chosen to skip this test, to focus on development of their 2015 car, while Lotus' new challenger only arrived in Jerez late this afternoon. The team hope to run the car tomorrow, with three days still remaining of this test.

Image source, AP

There is plenty of work to do for McLaren, though, the Woking-based team managing just six laps as they begin their new era with Honda. Jenson Button will take over from Fernando Alonso tomorrow.

Image source, AP

World champions Mercedes will be pretty happy with how day one went as Nico Rosberg clocked up a mammoth 157 laps. Lewis Hamilton will be hoping for similarly good reliability tomorrow when he gets his hands on the car.

1) Sebastian Vettel (Ferrari) 1:22.620 60 laps

2) Marcus Ericsson (Sauber) 1:22.777 73 laps

3) Nico Rosberg (Mercedes) 1:23.106 157 laps

4) Daniel Ricciardo (Red Bull) 1:23.338 35 laps

5) Valtteri Bottas (Williams) 1:23.906 73 laps

6) Carlos Sainz Jr (Toro Rosso) 1:25.327 46 laps

7) Fernando Alonso (McLaren) 1:40.738 6 laps

Sebastian Vettel finishes fastest on the first day of pre-season testing in Jerez.

McLaren's Fernando Alonso tweets:, external "First laps. So proud of my team. #happy." The fact he is tweeting suggests his running is done for the day.

Image source, Lotus

Lotus:, external The Eagle (E23) has landed...

Unfortunately, it's a bit too late for Lotus to get any running under their belt today. Pastor Maldonado was due in the car.

Carlos Sainz Jr has popped out for a late spin in the Toro Rosso while Nico Rosberg clocks up his 150th lap of the day. A remarkable effort from the Mercedes driver.

Only Nico Rosberg, Sebastian Vettel and Marcus Ericsson are circulating at the moment, with just 20 minutes of the session remaining.

Image source, Williams

After completing 61 laps, Valtteri Bottas heads into the garage to look through the data and have a chat with his engineers.

Andrew Benson
Chief F1 writer

Image source, AP

"Fernando Alonso has still managed only six laps today and McLaren chief executive Ron Dennis and racing director Eric Boullier have been holding a news conference while the team work on trying to get their car back on track.

"Dennis has been waxing rhapsodic about the quality of design and workmanship on the new MP4-30. 'The rear bodywork of our car has been brilliantly shrink-wrapped around a fantastically advanced and incredibly compact Honda power unit,' he said. 'We've even invented a new phrase to describe its design philosophy - the size-zero F1 car.'

"Dennis indicated that he was not too worried about the car's lack of running, caused by what the team say are 'a few niggly problems'. But even allowing for this being the first day of their new partnership with Honda, six laps - to follow on from the five they managed over two days in Abu Dhabi last November - has to be something of a concern."

Sauber's Marcus Ericsson goes second fastest, just 0.087 off the pace set by Ferrari's Sebastian Vettel. That would suggest nothing can be read into headline lap times.

Red Bull design chief Adrian Newey tells BBC F1 pit-lane reporter Tom Clarkson: "Good first day. The car is a decent step forward, but it'll be difficult to mount a serious title challenge."

McLaren:, external "Ron Dennis: 'Our 2015 livery will change, but I'm not going to say when...'"

Interesting!

The green flag is out, which means the session is back under way. Valtteri Bottas is straight back out in the Williams, as is Marcus Ericsson's Sauber and the Mercedes of Nico Rosberg. Ferrari's Sebastian Vettel is not too far behind.

There's a lull in the action, as the red flag is still out. Just 50 minutes to go...

Image source, Getty Images

Max Verstappen has to wait until tomorrow for his first chance to get behind the wheel of the new Toro Rosso, so the 17-year-old has instead spent the day following the action from the pits.

Woops, commentator's curse. The red flag is out for the second time today as Toro Rosso's Carlos Sainz Jr has rolled to a halt.

Image source, Reuters

Sebastian Vettel goes even quicker, the Ferrari driver moving 0.4 seconds clear of the field with a 1:22.690. Meanwhile, the driver who he replaced, Fernando Alonso, is bottom of the timesheets having completed just six laps in the McLaren.