Welcome back for the start of the second free practice session of the Australian Grand Prix.

Webber led the way in FP1 after a very good showing from Red Bull, but there are still plenty of questions to be answered. Will we see Ferrari et al fight back in FP2? What kind of lap times will the soft tyres produce? And will the degradation be less severe? Hopefully we'll get a better idea over the next 90 minutes.

The session is underway with Perez and Alguersuari hitting the track first.

Perez runs wide immediately on his first flying lap. He's out on hard tyres again, no damage done to the car.

Perez set his first flying lap with a 1:30.660 and is now hounding down di Resta. The come up behind Rosberg, but he's not giving way either... if the racing is as good as this on Sunday we are in for a treat.

In the last half hour of this session the FIA will conduct a simulation of race conditions with the moveable rear wing. So drivers will only be able to use it on the main straight when they are within a second of the car in front at the timing line.

Red Bull has told Vettel that he has to use his rear wing under race conditions for the duration of his current run and not just the last 30 minutes. Bare that in mind when looking at the times.

Hamilton is currently fastest with a 1:27.056, 0.392 up on Rosberg.

Webber is clocking times 3 seconds off Hamilton and is not using his rear wing. That suggests he is running a race simulation and getting used to a heavy fuel load on these hard tyres.

Trulli runs wide at turn three. That's the same car that Chandhok binned in the barriers earlier today. It's clearly not an easy car to drive, Trulli had armfuls of lock on and the car just careered straight on.

Ferrari says: "Fernando came in just after one timed lap just to check something in the car."

Alonso is currently seventh fastest and Massa is fourth.

The BBC is reporting that HRT will try and get one car out today for some installation laps.

Vettel complains of vibration as he starts his 14th lap on the same set of hard tyres. He's 16th fastest but we know he's not using his wing and is most likely on heavy fuel. Clearly a race simulation.

Eustace says: "To all those that said McLaren won't have a good car start of the season... I forgive you for that mistake"

It certainly looks like the car is quicker than it was in testing. Hamilton is still on top with a 1:26.961.

There is some light rain falling on track. Red Bull is forecasting that it will pass over the circuit in the next five minutes.

Neville says: "Surely HRT must be crazy to throw money at such a half-hearted effort. What are the chances of even qualifying and then getting into the race with a moving chicane."

Button sets a new fastest lap of the weekend with a 1:26.706. He's gone fastest by 0.255 on the hard tyres. Meanwhile, Alonso pops up to fourth.

Barrichello is out on the soft tyres.

Schumacher is also out on the softs and sets a 1:26.590 to go fastest of all.

Schumacher looked as if he could go even quicker on his next lap but peeled into the pits.

A bit of bodywork just detached from Heidfeld's Renault as he pounds round on the hard tyres. He's completed 11 laps so far.

Hamilton is now on a quick lap on hard tyres but comes across Maldonado in the final sector and it will only be good enough for third fastest.

Buemi is off the track at turn six, just lost the rear of the car on turn in and ran across the gravel trap.

Webber is out on soft tyres and runs wide on his first attempt at the first corner.

Petrov locks up and runs wide into turn 14. It looked like he completely missed his braking zone.

Button is out on track on the softs and sets a 1:26.156 to go fastest once more. He backed off immediately after the lap, possibly to try and save the tyres for another run.

Hamilton sets the fastest time with a 1:25.986 as Red Bull also attempt soft tyre runs but fall short.

Just three minutes remaining until the FIA enforces race-style conditions for the use of the rear wing. Will we see one last flyer from someone?

Alonso throws his hat into the ring with the third fastest time, just 0.147 seconds off Button.

Lotus has had a difficult first day back. Mike Gascoyne says: "Fuel pressure problem problem for Jarno and engine misfire for Heikki, both now fixed, tough day at the office today"

Vettel shoots up the timing screens to fourth with a 1:26.014. He's 0.160 off the pacesetter Jenson Button.

We're now into the final 30 minutes of the session, so we should only see the rear wing deployed on the main straight for overtaking purposes. Rosberg isn't using it on track so that seems to be the case. That could cement Button's place at the top.

Lotus just had to remind Trulli that the rear wing is now disabled. We'll keep an eye out for any overtaking manoeuvres.

Just 20 minutes remaining now. Button is out in front still and back out on track .

Alonso is heading back out on the soft tyres. Hamilton and Webber are also back out on track.

Hamilton has opted for the harder tyres on his latest run. He's 11 seconds off the pace after making a mistake into turn one.

20 cars are out on track at the moment as the drivers try to extract every last bit of information from the tyres ahead of tomorrow's final practice and qualifying sessions.

Vettel just used his rear wing while chasing Alonso down the pit straight. But it wasn't enough for him to make a pass. It's also starting to drizzle so he may have backed off.

Alonso then tries to use his wing on the Toro Rosso of Buemi with no luck. Race control has now declared a wet track so that's probably the last we'll see of the wing.

The top seven cars, which are made up of two McLarens, two Ferraris, two Red Bulls and Schumacher are split by less than a second.

Of those seven cars all but the Red Bulls are back on track.

And more significantly HRT have hit the track with Liuzzi at the wheel. He has got just two minutes to shakedown that car.

Webber is out of his car so no more practice for him.

The session come to an end with Button holding on to the No.1 spot.

© Sutton Images

The updates to the McLaren appear to have had the desired effect, although there is almost certainly more to come from all the top teams in qualifying tomorrow. Make sure you keep checking the site today for all the reaction from the teams and drivers.