Australian Grand Prix, Albert Park, 25-27 March
Practice: Friday 25 March, 0125-0305 and 0525-0705; and Saturday 26 March 0255-0405, Red Button, online and 5 live sports extra
Qualifying: Saturday 26 March 0500-0730 on BBC One, BBC HD channel, Red Button, online and 5 live sports extra
Race: Sunday 27 March 0600-0900 on BBC One, Red Button, online and Radio 5 live sports extra
Highlights - Australian GP second practice
By Sarah Holt in Melbourne
McLaren put their winter struggles behind them by setting the fastest time in practice for the Australian Grand Prix in Melbourne.
Jenson Button set the pace in an updated McLaren with a lap of one minute 25.852 seconds to edge his team-mate Lewis Hamilton by 0.132secs.
Ferrari's Fernando Alonso was 0.147secs behind in third ahead of Red Bull's Sebastian Vettel and Mark Webber.
Qualifying for the race starts at 0600 GMT on Saturday.
McLaren struggled for pace and reliability in pre-season testing, but they made major modifications to their car for the opening race, abandoning their radical 'octopus' exhaust system for a design similar to those used by Red Bull and Ferrari, as well as adding a new front wing.
Team principal Martin Whitmarsh had predicted the upgrade would see them close the gap on pre-season pacesetters Red Bull and Ferrari by up to a second and the signs are McLaren have moved forward.
"The surprise of the session is McLaren, in qualifying mode with free use of the moveable rear wing," said BBC F1 pit-lane reporter Ted Kravitz.
McLaren duo upbeat after practice
"Button's 18-lap run on a single set of tyres in first practice showed remarkably little tyre drop.
"This new exhaust system and the new front wing has definitely delivered the improvement they were looking for. Whether it is one second per lap, we'll have to wait and see in qualifying."
Button himself was delighted his MP4-26 had completed 61 trouble-free laps.
"Reliability something we've not had all winter, so to have a car that runs for as many laps as we want it to is very satisfying," he said.
"It also means we can get stuck into our set-up work and improve the car. I don't think there's much to be gained from looking at today's times though, so I'm not going to get too carried away.
"The new exhaust has definitely brought performance to the car - it feels much better, makes the handling more 'complete'. When you have downforce at the rear, you can also add it at the front, and then you put temperature in the tyres - there's so much that comes with downforce."
Hamilton was similarly pleased but cautious.
Chandhok crashed on his first lap of practice in the Lotus
"The grip level today felt like a big step forward," he confirmed. "We don't know what fuel loads the others are running, but our car feels like a big improvement from where we were just a few weeks ago."
Red Bull had held sway at the parkland circuit in the first session but eyebrows were raised over their tyre wear when they returned to the pits with chunks of rubber visibly missing from their tyres.
Team boss Christian Horner later explained that Vettel had damaged his tyre on a rogue piece of debris.
Red Bull settled for fourth and fifth in the afternoon standings, with Vettel's best time just 0.160secs behind Button's benchmark, but the German was not displeased with his day's work.
"I think we got a good idea as to where we are compared to our competitors," said the world champion.
"All in all I think we can be pleased, it seems we are not too bad, but we have to wait and see."
With the cars undergoing continuous work between the final test in Barcelona and first practice in Melbourne, the teams had much to learn on Friday.
Ferrari took the opportunity to run aerodynamic tests on both their cars. Alonso evaluated a new front wing and Felipe Massa ran "FloViz" paint to assess the airflow over a new rear wing during their early running.
Alonso, who set the third fastest time in both sessions, was consigned to the pits for a while in the second session, but the issue was soon solved and he improved his best time to just 0.147secs behind Button.
The Spaniard said the practice sessions had not revealed the real relative strength of the teams.
"As far as strategy is concerned, we will need to be very flexible during the race, because at the moment we know too little about the tyres to be able to say with certainty on which lap it will be best to stop," said Alonso.
"From what we have seen today, maybe we can do ten laps on one set of tyres, or maybe thirty!"
Mercedes also wanted to run the rule over the updated car they successfully debuted at the final Barcelona test.
The German team ran at the sharp end in both sessions, with Nico Rosberg fourth fastest in the morning and Michael Schumacher sixth fastest in second practice.
The seven-time world champion was 0.736 secs off the leading time in the afternoon but 0.858 secs faster than Rosberg, who was 10th.
From what we have seen today, maybe we can do ten laps on one set of tyres, or maybe thirty!
The new regulations also gave the field plenty to think about, especially the return of tyre supplier Pirelli in place of Bridgestone.
There is a belief across the paddock that tyre management and strategy will be a key factor in determining the outcome of races this season as the Pirellis have been designed to degrade much more quickly and have greater performance differentials than Bridgestone's rubber.
As a temporary track, Albert Park evolves significantly as the grand prix weekend continues and the city's fickle weather adds to the difficulty of predicting form for qualifying and the race.
There was further bad news for Hispania. Despite working through the night in an effort to prepare their cars for practice, the cash-strapped team - which did not participate in any of the pre-season tests - only managed to get a single car on track in the final two minutes of the second session. Vitantonio Liuzzi completed a single installation lap before returning to the pits.
The return of the 107% qualifying cut off means Hispania are not the only team concerned about making the starting grid.
Virgin's fastest time was outside the theoretical cut-off, and driver Timo Glock admitted their prospects did not look strong.
"The only chance we have is that the top guys in Q1 run the hard tyre and we run softs and then we don't have a problem to get within 107 per cent," he suggested. "It's disappointing and not great that the car is not on the pace."