Welcome to Silverstone for the final practice session ahead of qualifying. The big news is that McLaren has decided to ditch its latest update - the blown diffuser - after a difficult couple of Friday practice sessions.

In this session we can expect to get a slightly better idea of how the drivers stack up as they complete soft tyre runs on fuel loads closer to the ones we will see in qualifying.

Red Bull appears to be the team to beat after the first two practice sessions and there is no reason why that should change today. The RB6 is still the fastest and most stable car through the high-speed corners, and that is absolutely crucial at Silverstone.

The drivers are getting ready to step into their cars and head out on track. It's an hour long session that the teams tend to use to find their final set-up ahead of qualifying.

Trulli is the first to head out into the pits and he gets the green light to go out on track. He is followed by Kovalainen and Chandhok in the HRT.

Trulli got next to no running yesterday so will be keen to put some mileage on his Lotus this morning. The two Lotuses return to the pits after their installation lap.

Hamilton is out on track with the standard exhaust system on the back of his car.

All the cars have now been out for an installation lap just to make sure the radio and systems are still working after being worked on overnight.

Leonard asks: "How much the fuel (i:e. shell, petronas, etc) effect the performance of the engine, raw speed of the engine or the overall consumption? Have there any real test on the performance of the fuel?"

A fair bit but it is much about cooling and fuel consumption as performance. Each oil is developed specifically for the engine it is used in, so it's quite difficult to make direct comparisons. However, there is plenty of money thrown at the area so it is fairly important.

For those asking, Formula One Management do not allow us to show live timings. I will try to keep you up to date with the most important laps.

At the moment nobody has set a time, although Jarno Trulli is heading out on track now.

Most of the top drivers are stood beside their cars, so we might have a bit of a wait until we get some meaningful lap times.

Virgin want to make the most of the empty track: "Ok. Off we go. Both cars running now. Hope they will get some clear track time"

No dramas at Mercedes: "Very calm in the garage at the moment as we wait for the action to get underway..."

Bad news for Virgin, Timo Glock has got no drive coming out of club corner. He complains of a throttle problem over the radio and is told to return to the pits in a high gear.

Sparks fly off Kovalainen's undertray as he enters Maggots corner. More sparks as he crashes over the bumps heading into Abbey, the car is obviously running quite low - possibly heavy with fuel.

Virgin is hoping Glock's throttle problem will be a quick fix. Dave is on the job: "Timo in the pitlane. He has a throttle problem which dave is confident we can fix quickly"

Alguersuari is now the quickest driver out there but is still three seconds off yesterday's pace with a 1:34.692.

Button is now out on track and immediately runs wide at Abbery on his first lap. McLaren are really struggling through there this weekend.

McLaren test driver Gary Paffett says it is "disappointing" that the team had to take the blown diffuser off the car but says it has to "stick with what they know". He has been in the simulator all night trying to understand what went wrong.

Carl asks: "This year we've heard a lot about drivers being forced to go back to their test-chassis. In previous years I've never heard of it. Is their a limit to the amount of chassis a team/driver can have per season? And is this because of the cost-saving-nature that F1 is now involved in?"

Yep, I think it is cost saving. Also a lot of work is going into the development of the car rather than building new chassis. But, barring crashes, there is no reason why a driver won't stick with one chassis for the entire season.

Kubica is fastest on a 1:31.818, ahead of Barrichello on a 1:31.835. Rosberg third: 1:31.960. All times have been set on hard tyres so far.

Alonso and Webber are heading out for a proper run. The track will now get a lot busier as the cars out earlier have cleared away all the dust that settled on the track overnight.

Sutil has a massive moment exiting Copse as he runs over the kerb. Somehow he manages to hold onto the slide.

Alonso goes fastest on a 1:31.580 and is lapping very quickly now on his next attempt. Overnight Ferrari reported that it is very happy with its blown diffuser.

Alonso goes even quicker with a 1:31.351. Webber's fastest time yesterday was a 1:31.234. We can expect low 1:30s in qualifying, possibly a lap in the 1:29s. Of course, that will be on very low fuel and soft tyres.

Glock is back on track, throttle problem solved. "Timo is the only driver not to have set a time. Just starting his first flying lap," says Virgin.

Webber is about two or three seconds off the pace but is currently working on race set-up and old hard tyres.

Alonso sets a new fastest time with a 1:31.101. He is 0.324 up on Vettel.

Massa is currently lapping 0.522 off teh pace of Alonso but we don't what their fuel loads are.

Speed trap data:
Button: 300 km/h
Sutil: 300 km/h
Liuzzi: 297 km/h
Rosberg: 296 km/h
Petrov: 296 km/h
Schumacher: 295 km/h

Schumacher runs wide through Brooklands, he appeared to take the apex much earlier than the other drivers through there - possibly trying a differnt line, possibly a mistake.

Vettel sets a 1:31.039 to go fastest.

Trulli's session is over with a locked differential. Liuzzi is also suffering hydraulic problems.

Vettel breaks into the 1:30s - just 0.143 up on Alonso. Vettel returns to the pits and with just over 10 minutes remaining we can now expect some soft tyre runs and quicker lap times.

Sutil is out of the car so that's the end of his session - not sure what the problem is down there but he doesn't look that happy.

Yamamoto is one of the only drivers out on track and is having to lean his head against the side of the cockpit to give his neck a rest from the high g-forces.

Suspected gearbox problem for Adrian Sutil - that could drop him down the gird if he has to change it.

All the big names except Alonso are now out on soft tyres. Massa goes third fastest on his first lap on softs, Alonso's car is in pieces in the garage he won't be rejoining this session.

Webber is now second fastest with a 1:31.098.

Vettel is now on a fast lap as his competitors try to find some space on the track for a quick one.

Vettel runs very wide through Abbey and the nose of the car has dropped down. It happened over the bumps and he lost all front downforce. No big damage done but very, very concerning for the team.

However, at the moment no one looks capable of challenging Vettel's time.

The chequered flag falls and Vettel does hold onto the fastest time but there are big concerns about his car for qualifying. Webber was just 0.034 off his Red Bull team-mate and Alonso was 0.143 further back.

Thank you for joining us, make sure you check back for qualifying in two hour's time.