Welcome to live commentary of the first practice session for the Chinese Grand Prix. The pit lane is about to go green in Shanghai.

The circuit is a little damp from some overnight rain but we are expecting a dry session.

Kovalainen and Kobayashi get the action underway at the Shanghai International Circuit.

A mix of medium and wet tyres out there at the moment, although Massa has gone out on medium compound slicks.

Installation laps are either underway or completed for all the drivers apart from Hamilton, who's having some minor tweaks to his McLaren before heading out.

Big news this morning is, rather predictably, about the Bahrain Grand Prix as the FIA has said it will go ahead. Read the statement here.

John says: "I'm expecting a McLaren/Mercedes front 4 lock out for quali this weekend. Question, what's your view on Mercedes tyre issues and can the issue have been resolved during the 3 weeks off in the factory as Ross has mentioned? Surely more running would be required to be fully certain?"

I agree that they won't know for certain until they complete some dry running today and tomorrow. The tyre operating windows are so small this year that I would be surprise if they nailed the problems straight away, but it's also true that they have plenty of room for improvement so will no doubt have made some improvements. It can't get much worse!

Hamilton is out on track on medium tyres with a wide sensor across the back of his McLaren. An obvious sign that McLaren is testing its new parts this morning rather than chasing set-up and lap times.

We've yet to see a driver set a lap time as we wait for the first man to hook up all three sectors consecutively.

Alonso has what looks like litres of flo-viz paint on the rear wing of his Ferrari. There are five updates to the F2012 this race so the team has its work cut out to understand them all and get them working.

Robert says: "Good to hear about Bahrain going ahead, I was wondering what would happen if it didn't?"

There's still a fairly big question about what will happen when it does go ahead. There has been some threats of protests, but the FIA are happy everything will be secure so we have to trust that they have the solid information.

We're still waiting for that elusive first timed lap. Lots of work for all the teams to do as they all try to get a baseline understanding of the upgrades they have brought here.

Schumacher heads out on the medium tyres, but its still a little damp out there. Nobody seems that keen to go out and attack the track at the moment.

Red Bull are running two different exhaust systems on its two cars this morning. Vettel is running the exhaust that the team started with in early testing whereas Webber is using the updated version that was first brought to the final two days of testing and then developed at the first two races.

Ryan asks: "Can someone please tell me why senna isn't racing? Who is Bottas?"

Bottas is Williams' test driver and is just standing in for the morning practice session. Meanwhile, Bianchi is driving di Resta's Force India and van der Garde is in Petrov's Caterham. All the race drivers will be back in their cockpits for second practice this afternoon.

Some reports of rain out there as Webber sets a 1:44.542.

Webber improves to a 1:40.647. It's very gloomy out there but the track does appear to be drying.

Ricciardo sets the second fastest time with a 1:42.763 but has sparks flying from the rear of his car. It looks as though the Toro Rosso is running way to low but he's staying out on track at the moment.

Medium tyres are the compound of choice at the moment, but an onboard view with Massa shows rain drops starting to fall. The Ferrari runs wide in turn nine to prove just how tricky its getting out there.

Reports of a suspension problem on Ricciardo's car. The Toro Rosso mechanics are investigating the rear of his car.

The rain is falling harder now.

Paul on Bahrain: "The F1 authorities and some fans seem to think that it is possible to ignore the human rights situation in Bahrain. There are many fans like me who think Bahrain should be vetoed by F1 because of the way the government there is conducting itself. There are bigger things in life than motor racing, and F1 has the power to make a difference here."

Lots of cars running wide on track now as Pic fails to get the front of his Marussia to grip in a slow speed corner. It's a shame as we were hoping for more running in this session but the weather is not playing game.

Only the top ten cars have set times so far this session and we are already half way through.

Vivek asks: "How do tire options work in wet conditions. Only rule i know is that both the compounds need to be used at-least once in a race. Does it still apply in a wet race? Also does engines also vary for different tracks like aero packages?"

As soon as race control declares a race wet then the drivers do not have to use both compounds. The engines remain largely the same from race to race; drivers have eight engines they can use over the course of the season, but the teams decide strategically when to use a new engine so as to make the most of the extra power at certain circuits.

Caterham on the conditions: "The rain arrived, so both drivers are back in the pits now waiting for better conditions"

Adam: "As it looks like it will be raining for the race wouldn't it be beneficial for the teams to get in as much time as they can if it raining so they can better understand the cars for the race? Also what is your view on Ferrari could you see them pulling out of the sport like Honda and others have if they don't start winning again in the next few years?"

Because wet conditions mean the track is constantly changing, it's always difficult to learn a huge amount during a practice session that will be directly relevant to a race situation. Some teams head out to judge when is the right time to change from wets to inters and then to slicks, but even that isn't an exact science. There's also the danger that the driver will make a mistake and the team will have to spend the rest of the day putting the car back together.

To answer your second question, I would so absolutely not. Ferrari has been competing in F1 since 1950 and have had much worse cars than the F2012 to deal with.

It's now very gloomy out there. Alonso is running a constant-speed test on medium tyres and really struggling for grip. Proof that there is still some work that can be carried out in these conditions.

Glock holds a huge slide through turn 10. Impressive stuff as he's also out on the medium tyres completing constant-speed tests.

A constant-speed test is pretty much what it says on the tin. The teams do them to gather aerodynamic data which they then compare to the data they have been getting from the wind tunnel on new parts.

Fortunately this circuit has huge run-off areas so any mistakes aren't too harshly punished when running at low speeds.

McLaren says it is still running the cracked gearbox on Hamilton's car to see if it will make the race, but team principal Martin Whitmarsh says it's still very likely they'll change it for qualifying and take a grid penalty.

Grosjean is out on intermediate tyres at the moment and, to give an indication of the conditions, is nine seconds off the pace of Webber's fastest time.

Raikkonen is told the DRS is not working properly and that he has to manually switch it off, suggesting it was not closing automatically under braking.

Perez holds a big slide in the Sauber. Judging by his performance in Malaysia, he should be a master in these conditions.

Conditions are still pretty grim out there but the drivers are heading out. The forecast is for similar conditions throughout the weekend so it looks like they have accepted that they are going to have to get used to it.

Raikkonen is out of his car and that may well be the end of his session. He was struggling with his DRS which is not a problem you want to have in these slippery conditions.

Perez is all over the back of Button on track. The Sauber is now back on medium compound slicks whereas Button is on inters.

The inters are literally melting in these conditions and offering very little grip.

Lotus tweets: "Kimi's session over, we've used up a set of inters on the semi-dry track. Time for an ice cream"

Alberto says: "Hi from Tasmania - where its very sunny! So with rain falling on Sunday - what's your prediction for the level of carnage the moving chicane (Karthikeyan) will inflict? How long will they give him before they put a sound driver in his seat?"

While I have no doubt that Karthikeyan's place in F1 is linked to the money he brings to the team, it is a little harsh to blame him entirely for the collisions in Malaysia. Button admitted his collision was his fault and you could certainly argue that the Vettel crash was 50/50 in blame.

Webber is setting some fast sectors as Schumacher clocks a new fastest time with a 1:39.318.

Webber immediately takes the top spot back with a 1:38.977.

Grosjean is out of his Lotus early but has a big smile on his face.

Hamilton is now on a fast lap as Vettel reports that his DRS is no longer working.

Hamilton lost time in the third sector and has to settle for the third fastest time.

Perez goes fourth fastest and looks confident in these conditions, as he did in Malaysia.

Hamilton goes fastest by 0.8s with a 1:38.146. Schumacher is still the fastest man in the middle sector but the McLaren was supreme in sectors one and three.

Perez slots in second fastest with a 1:38.584.

Hamilton clocks a time a second clear of the rest of the field with a 1:37.106. Rosberg went fastest for a couple of seconds but will finish the session second with a 1:38.116.

So the session ends with a flurry of fast laps as the conditions improved in the final 15 minutes. It was a fairly frustrating session for most and the drivers will be hoping for drier conditions in the afternoon.

We'll be back in two and half hours for FP2.