Welcome to the third and final practice for the Chinese Grand Prix. This should be an interesting session as we see the cars running close to qualifying trim ahead of the all-important session this afternoon.

Paul di Resta heads straight out for the start of the session and he is followed by at least ten cars also keen to get work underway this morning.

Sebastian Vettel was fastest on Friday, just over a tenth faster than Lewis Hamilton's McLaren. Both McLaren drivers said there is more time to be found in the car yesterday so we could have a close battle for pole position later today.

All the cars have completed an installation lap and are either back in the pits or staying out on track. Michael Schumacher has a minor problem with his brakes pulling the car to the left, but the team is confident it can be easily fixed.

The track has fallen quiet as the teams make some minor adjustments ahead of teh first proper runs of the day.

It's a bit colder than it was yesterday with air temperature at 15C and track temperature at 15C. Once again it is cloudy overhead, although a little less smoggy.

Renault's weather forecast says: "No rain predicted in next 30 mins, waiting for a few cars to go out then we'll be on our way"

di Resta is back on track and should provide us with the first timed lap of the day.

di Resta clocks a 1:40.459 after a small mistake into the hairpin. We can expect much quicker times than that before the end of the session.

There are reports of low grip out on track which could be down to the windy conditions blowing dust on to the track over night.

Ferrari syas: "This session is more important than usual for Fernando, who lost precious time yesterday afternoon."

He suffered an hydraulic problem that kept him in the garage for much of FP2.

Ron asks: "Is an 'Installation lap' compulsary ?"

It would seem that way, but the teams can use this session however they wish. They complete an installation lap in this session just to check that the car is running as it was yesterday and all the telemetary is coming through as expected.

For those asking, we are not allowed to show live timings.

I can tell you, however, that Button has just gone fastest with a 1:37.367.

Hamilton locks his front right into the hairpin but goes on to set a 1:37.321, which is immediately pipped by Sebastian Vettel by 0.026 seconds - the fastest so far.

All times have been set on hard tyres so far and Hamilton is having to weave on the long back straight to get some temperature into his rubber.

Vettel has now gone even quicker witha 1:36.053.

Only 30 minutes of this session is left now. We should see drivers bolt on some soft tyres pretty soon and attempt a lap in qualifying trim.

Hamilton returns to the pits with teh fourth fastest time.

It will be interesting to see how Mercedes get on this weekend. Both drivers were very positive about the car after practice - which is a first for this season - and so far have been setting competitive times.

Sutil has a huge lock up into the hairpin, but the only damage will be to his tyres.

Webber appears to have a KERS problem as the Red Bull mechanics don rubber gloves to protect themselves from electric shocks. He hadn't used any of it on his last run and ran wide into turn six. He returns to the pits and his team puts a KERS warning sign on the top of the cra - not good. Meanwhile, Vettel heads back out in his RB7, which appears to be working perfectly so far.

Webber's issue might extend further than KERS, however, as the mechanics are also taking a good look at the front right wheel and brake. It's remarkable how the No. 2 Red Bull has suffered so much more bad luck than the No. 1 car this year.

Ferrari says: "First run completed with a practice start for Fernando, who is currently 4th in 1.37.207. Felipe is doing the same work, 6th in 1.37.347"

Schumacher and Rosberg are out on soft tyres. Schumacher has gone second fastest 0.088 off Vettel's quick lap.

Rosberg goes quickest with a 1:35.677.

Good news for Webber fans, he's back out on track after that short spell in the pits. Hopefully he'll clock his first lap of the day...

Alguersuari has a huge moment at the final corner and runs wide in a huge slide on the Astroturf. It was a little bit like being transported back to the 1970s, when cars would slide and drivers had sideburns.

Webber is on hard tyres at the moment but is not using KERS. He goes sixth fastest with a 1:36.869.

Soft tyres are being prepared in the pit lane. We should be about to see the front runners attempt a dress rehearsal for qualifying.

Webber is back in the garage. The rubber gloves are still out on Webber's side of the garage and clearly all is not quite right.

Alonso starts a lap on the soft tyres - what kind of lap time has he got locked in the Ferrari?

Alonso goes fourth fastest, 0.5 seconds off Rosberg. Not good for him, but we don't know fuel loads.

Massa has now gonme fastest in the first sector in the Ferrari so clearly there is some time to be found in that car. He was told to shift earlier after his last lap after hitting the rev limiter.

Massa goes second fastest with a 1:35.971, he is still 0.294 off Rosberg.

Button goes 0.5 seconds faster than Rosberg but Vettel is about to pip him... and does it with a 1:34.968. For the record his KERS is working, but possibly not to its full potential.

Hamilton runs wide in turn one and off the circuit, which won't be good news for his option tyres.

Meanwhile, Webber car is still in the pits and he will not take any further part in this session.

Vettel has also returned to the pits and is likely to hold on to the top spot.

Peter says: "Obviously the RB team seems to be treating the no 1 car as the priority car, and Webbers car is not getting the attention it needs. I cannot understand why the system is working on the no1 car and not the no2 car. Why not just remove it and its associated weight, or do they have to run with the system in place?"

Nope, they could ditch if they want to, but it is worth an awful lot of acceleration at the start of the race and that can be the difference between winning and losing a grand prix.

Hamilton goes third fastest with a 1:35.373. But remember he ran wide in turn one on his previous lap and that will not of helped his tyres.

The session is coming to an end and it looks as though Vettel will hold on to the fastest time.

D'Ambrosio has a bit of a scare on the exit of turn 13 as his front wing shatters as he runs on to the kerbing. Not good for him and it has left debris on the racing line for everyone else.

Not that it matters too much as nobody was on a quick lap.

The session comes to an end with Vettel leading from the two McLarens once again, but all might not be well with the Red Bull KERS.

Pretty much the story of the season so far. Join us in two hours for the next chapter as qualifying gets underway at the Shanghai circuit.