15:00 The formation lap is underway. Webber is starting on hard tyres, so he will go long in to the first stint to try and leap frog cars in front. Schumacher, Maldonado and Heidfeld are starting on softs.

Webber might attempt a one-stopper here. It is just about possible according to Pirelli and is a significant advantage if you can nurse the tyres.

14:59 The grid clears of mechanics, all the engines have been fired up and the tyre covers are off.

14:55 The latest from McLaren is that they have replaced the air filter and everything that was flooded with fuel. The car will start but it's not the ideal preparation for 56 lap race.

14:52 It's relatively warm here and the track temperature is at 29C, about 6C up on yesterday's qualifying.

14:50 McLaren's Jonathan Neale said Hamilton's engine was flooded. The team is not sure why and there is still plenty of work going on on the grid. They have three minutes to sort it, Neale is confident they will do it.

14:44 As I type, the engine cover goes back on and with 20 seconds remaining he heads down the pit lane. He will make the grid but there may well be a problem. We'll keep a close eye on Hamilton to let you know.

14:42 The BBC is reporting a fuel leak on Hamilton's car and the team is surrounding the rear of the McLaren with fire extinguishers as they try once more to fire it up. It is looking less and less likely that he will make the grid.

14:40 Really bad news for Lewis Hamilton, he is stuck in the garage with the engine cover off and his mechanics have just 5 minutes to fire it up and get him to third place on the grid.

14:36 Sebastian Vettel is undoubtedly the favourite to win, but the most exciting man to watch in this race will be Mark Webber who will be fighting his way through the field from 18th on the grid.

14:35 Hello and welcome to commentary for the Chinese Grand Prix. It's race day in Shanghai and we look set for a dry couple of hours ahead. Pirelli are expecting two-stop strategies with the possible of one-stopping if drivers are gentle on their tyres. In short it won't be quite as frantic as the Malaysian Grand Prix one week ago.

Lap 1

Button and Hamilton lead in to the first corner and Rosberg is attacking Vettel but loses out and finds himself defending from the Ferraris.

A good start by the Force Indias too in seventh and eighth ahead of Schumacher. Webber has not made up much ground and judging by the speed differential to drivers around him is not using KERS. He is 17th.

Lap 2

Button leads by 1.3 seconds across the line from Hamilton and Vettel. Webber moves up to 16th overtaking Perez. It's slow progress so far for him.

Lap 3

Button leads by 1.1 seconds on this lap and Hamilton is not quite close enough to use his DRS. It will become active on this lap.

Lap 4

Vettel is the fastest man on the track and is just 0.6 seconds off Hamilton. Looking at replay of his start he bogged down, used KERS but had no answer to the attacking McLarens.

Lap 5

Button is now fastest as Vettel comes in behind Hamilton's slipstream. Webber continues to make progress, moving up to 15th after passing Barrichello.

Di Resta is currently holding up a train of cars in seventh. Team-mate Sutil is closest but he is also coming under pressure from Schumacher. Kobayashi has also joined the back of that queue as di Resta complains of a lack of rear grip.

Lap 6

Vettel is still within a second of Hamilton, who is now 1.2 seconds off Button. The front runners appear to be holding station and are 2.1 seconds ahead of Rosberg who has two Ferraris on his tail.

Lap 7

Vettel is told that he is doing well by his team as he keeps the gap to Hamilton constant. The big question now is who will pit first and get the advantage of the fresh tyres. Of course they can't go too early otherwise they will compromise strategy. I expect we will see the first stopper around lap 12 or 13.

Lap 8

The two Toro Rosso's are battling on track but the DRS does not allow Buemi to pass on the long straight.

Webber is still back in 15th and not making the kind of progress he would have liked early in the race.

Lap 9

Button now leads by 1.4 seconds from Hamilton, who is still 0.5 seconds up on Vettel.

Perez is all over the back of Webber and passes him. A brilliant move but terrible news for Webber who is 23 seconds behind Button now.

Heidfeld gets past Buemi and Alguersuari pits, promoting the Renault to 12th.

Lap 10

Alguersuari has lost his right rear wheel after his pit stop and is limping back to the pits.

Lap 11

Schumacher pits from ninth and Webber is also in after a very slow in lap during which he lost a place to Barrichello. He comes out just ahead of Karthikeyan.

Webber took on soft tyres so clearly the strategy he started on was not working whatsoever.

Lap 12

Rosberg is coming under pressure from Massa while Alonso keeps a watching brief one place back in sixth.

Perez is making great progress and uses the DRS to fly past Buemi on the straight.

Lap 13

Rosberg pits and releases Massa in to free air. Meanwhile Schumacher has come out in front of di Resta after their pit stops.

Hamilton is within a second of Button now as the top three close up. McLaren made a move in the pit lane but it was a dummy to keep Red Bull on its toes as both cars stay out.

Lap 14

Vettel is now very close to Hamilton as his tyres start to fade. The team are still in the pits.

And Vettel passes Hamilton using the DRS.

Lap 15

Button and Vettel pit. But Button went in to the Red Bull pit box - a massive mistake. As a result Vettel takes position out of the pits. A bizzare set circumstances.

Meanwhile Hamilton has made a mistake and lost a position to Massa in the final sector. That has ruined his race. We haven't seen it yet on the TV screen.

Lap 16

So Vettel comes out of the first pit stops ahead of the McLarens, but Rosberg is the man leading the way after his early stop.

Impressive stuff from Mercedes, can they convert him on to a two stop?

Lap 17

Alonso now pits from the lead on the circuit and comes out behind Schumacher. Bad news for the Ferrari, he stayed out too long on his tyres.

Petrov is in the mix but has yet to pit and has now been passed by Vettel for second on the circuit.

Lap 18

A battle between Schumacher and Alonso is now shaping up for sixth as Hamilton is still stuck behind Massa ahead. Those two are actually quite close to Button, who is 1.5 seconds off Vettel.

Lap 19

Rosberg leads by 5.0 seconds ahead of Vettel. It seems as though Rosberg is on a three-stop strategy whereas Vettel is on a two-stop strategy, but can the Mercedes prolong the life of those tyres to change strategies? It will be very interesting to watch and depends on the evolution of the track.

Lap 20

Rosberg is keeping a decent pace at the front but lost 0.3 seconds to Vettel on the last lap. Meanwhile Button is quicker than anyone else and is 1.4 seconds off the Red Bull in front.

Lap 21

The best battle on the track is between Alonso and Schumacher for sixth. The Ferrari is trying to pass with the DRS on each lap but isn't quite fast enough.

Lap 22

Rosberg has now pegged the gap back up to 5.0 seconds from Vettel.

Meanwhile Webber is all over the back of Kobayashi who has some very minor damage to his nose cone.

Lap 23

Vettel sets a personal best and is now 4.6 seconds behind Rosberg, who has been told to lift off earlier under braking.

Lap 24

Alonso is still all over the back of Schumacher but can't find a way past. They are on different strategies - Schumacher three-stopping and Alonso two-stopping - but the Ferrari is losing time to Hamilton and Massa ahead.

Lap 25

Button pits which means he must be on a three-stopper. Some very strange strategies working out here.

Button is now going to start setting some very quick sectors.

Lap 26

Rosberg pits from the lead. Hamilton follows him in too. So Rosberg is looking very competitive compared to the McLarens.

Alonso passes Schumacher for sixth. He cut back underneath the Mercedes at the hairpin, a good move aided by the DRS.

Lap 27

Schumacher pits now. The big question is whether Vettel will have to pit as Rosberg is now closing on him again in every sector and 18 seconds behind overall.

We should also mention that Webber has taken on a set of soft tyres in his second stop and is now looking very quick as he chips away at the rest of the field.

Lap 28

But we mustn't rule out Massa either who is faster on track than Vettel, on the same strategy and now just 3.2 seconds behind now.

Lap 29

Rosberg passes Alonso with the extra traction out of the hairpin. The Mercedes is now just 12.4 seconds off Vettel and closing by roiughly a second a lap.

Lap 30

Now Button passes Alonso out of the hairpin. The Ferrari's two-stop strategy is simply not working for Alonso. Hamilton is also past the Ferrari now.

Rosberg leads Button by 2.4 seconds. Meanwhile Vettel, who is 12.2 seconds down the road, has lost his radio communication with his engineers - not ideal in such a changable race.

Lap 31

Hamilton is the fastest man on the track but the best battle is shaping up between Massa and Vettel at the front.

Lap 32

Sadly we won't see a scrap on track as Vettel pits for hard tyres - so that is his last stop. It was a tardy pit stop.

Hamilton is now on the back of Button as they take over fourth and third.

Lap 33

Webber is up to ninth and now on the back of a battle between Petrov and Schumacher. The Mercedes pulls a great move in to turn six on the Renault, which is on older tyres, and now it's Webber's turn to have a go.

Lap 34

Massa pits for hards and comes out just behind Vettel, pretty much as they were before the pit stops.

So Rosberg now leads by 1.7 seconds from Button but has to pit once more. As do the two McLarens.

Lap 35

Hamilton passes Button for position in to the first corner. It was a very clean fight but also a spirited one, Button did not concede position and it was a bit sketchy on the entry to turn one.

Lap 36

Rosberg is still faster than Vettel on track but the gap of 16.5 seconds is not enough for a final pit stop.

Lap 37

Hamilton is faster than Rosberg in front and has a 2.6 second gap to make up. He has a chance of beating him, but it will be another tight battle.

Lap 38

Button pits for hard tyres and comes out ahead of a ferocious battle between Schumacher and Webber.

Meanwhile, Rosberg's gap to Vettel is only 16.7 seconds - not enough for a pit stop.

Lap 39

Hamilton pits for hard tyres. He will now have to push very hard to close the gap to Massa and Vettel. He does come out ahead of Button, though, so holds position.

We've just seen a replay of Alonso using his DRS at the wrong place. He activated on the short run to the final corner. He didn't gain a massive advantage but that is against the rules.

Lap 40

Rosberg pits and comes out just ahead of Hamilton. The McLaren attempts a move in to turn six but the Mercedes is perfectly placed to keep him at bay.

Lap 41

Vettel resumes the lead, 3.6 seconds ahead of Massa, who is just 1.7 seconds up on Rosberg on fresher tyres.

Hamilton locks up in to turn six as he tries another move. But the pair of them are closing on Massa. But crucial to this is Rosberg's fuel load which, according to the pit radio, is running low.

Lap 42

Hamilton makes a move stick on Rosberg in to turn six as the Mercedes gets baulked by a Williams coming out of the pits. Hamilton is now 0.9 seconds off Massa and 4.9 off Vettel but lapping quicker. This is going to be a great finish.

Lap 43

Back on Webber watch, he's just set the fastest lap on his new tyres and is 4.8 seconds off Alonso in sixth position ahead of him.

Massa told that he is being caught by Hamilton. The gap is now 0.8 seconds, with Hamilton 5.0 seconds off Vettel.

Lap 44

Hamilton told that the best time to attack could be at the end of the race when Vettel's and Massa's tyres wll be "very old".

Lap 45

But Hamilton wastes no time passing Massa. He got a boost from his DRS in to the hairpin and then went side-by-side in the final corner and ahead in to the first corner. Great racing and a great move.

Hamilton is now 4.6 seconds behind Vettel and closing.

Lap 46

John Bates says: "Fabulous commentary; Who needs pictures, Cheers, "

Glad you are enjoing it, we certainly are as Button passes Rosberg unseen on TV. A replay shows that Rosberg went too deep in to the turn 14 hairpin trying to pass Massa and came out behind the Ferrari and Button under acceleration. Button is now on the back of Massa.

Lap 47

Vettel is responding to Hamilton with a personal best, but the gap continues close as Hamilton makes use of his fresher tyres. The gap is now 3.3 seconds.

Massa is 4.0 seconds off the top two but will be more concerned with Button and Rosberg who are all over the back of him.

Lap 48

The gap at the front is 2.9 seconds. Hamilton is told to protect his tyres and that Vettel will fall in to his clutches.

Perez comes together with Sutil for 11th place. The Sauber driver's fault in my opinion and some pretty hefty damage to Sutil's front wing.

Lap 49

Hamilton is now just 1.6 seconds off Vettel as they cross the line, surely this is now just a matter of time as seven laps remain in this grand prix.

Perez takes a drive-through for his contact with Sutil, or possibly his contact with Heidfeld earlier. He's been in the wars today.

Lap 50

Button gets past Massa towards the end of the last lap. Hamilton is now 0.9 seconds off Vettel.

Bakc on Webber watch, and he is storming through the field with fastest laps. He's just 6.4 seconds off Rosberg.

Lap 51

Hamilton all over the back of Vettel in the DRS zone, but the Red Bull defends its position well and gives Hamilton the option of running off the circuit or in to him in to the final corner. Hamilton wisely backs off and waits for another chance later in this race.

Rosberg storms up the inside of Massa for fourth in the final corner. The Ferrari runs wide and falls in to Webber's clutches.

Lap 52

Hamilton has another go at the end of the last lap but Vettel parks his car on the apex to stop him. Hamilton closes again in turn six and makes the pass on the inside of the high-speed turn seven. It was a great pass as Vettel struggles for grip and power now that his KERS appears to have failed.

Lap 53

Webber is now all over the back of Rosberg. Button is 4.6 seconds off Vettel.

Hamilton pulls a gap of 1.2 seconds at the front over Vettel, so now has to cruise to get his car home in first.

Lap 54

Hamilton increases the gap to 2.8 seconds as Button closes the gap to Vettel to 4.0 seconds.

Webber attempts a move on Rosberg in to turn six and then makes it stick in to turn seven. It was a great pass and now he is closing at a rate of knots to Button.

Lap 55

Two laps remaining and Button leads Webber by 1.2 seconds. Webber is on the soft tyres which are three laps younger than the McLarens.

Webber beats Button in to the hairpin using the wing but comes back strong in to the final corner to pressure the Red Bull in to a tighter line. Webber holds on though and now has a gap of 3.4 seconds to his team-mate.

Lap 56

Hamilton celebrates in parc ferme with McLaren managing director Jonathan Neale. Such a great result for McLaren, winning with an agressive strategy and a great race by Hamilton. He's overcome with emotion, fighting the tears as he prepares for the podium - emotions are running high for Hamilton.

Hamilton leads on to the long straight for the last time... he makes the hairpin, perfects the final corner and crosses the line for victory.

Vettel takes second, Webber a very impressive third from 18th on the grid and Button finishes fourth.

Rosberg takes his first points of the season in fifth, ahead of Massa, Alonso and Schumacher. Petrov and Kobayashi make up the final points positions in ninth and tenth.