After five months of waiting, the new Formula One season is finally underway, as the drivers prepare for the first of today's two ninety-minute sessions.

Most teams are to use their race drivers today, however, Williams will be using Kazuki Nakajima, which means we won't be seeing Nico Rosberg today, while Sebastian Vettel replaces Robert Kubica.

Furthermore, in respect of the new testing agreement, the engine rules don't apply, which means that drivers can 'go for it' without fear of a grid penalty.

With the teams having agreed to eight three-day test sessions during the season, the Friday sessions have been extended in the hope that there'll be more action as teams try out new parts.

With five minutes to go before the opening session gets underway, its dry but overcast. There has been rain this morning and further showers are forecast for the remainder of the day. This, combined with the fact that the track is already 'dirty' should make for a few thrills and spills in the opening session.

Having got used to seeing Ron Dennis in the infamous black outfits, it seems strange to see him in a white Vodafone McLaren Mercedes bodywarmers. And very nice he looks too.

We've also been treated to the much-hyped Red Bull promotional movie which sees the Red Bull duo go head to head with Toro Rosso, thereby giving a whole new meaning to one-make series.

Air temperature is 21 degrees C, while the track temperature is 24 degrees.

The lights go green and first out is Sebastian Vettel, followed by Trulli and Sutil. The track is still wet, consequently we see the familiar 'rooster tails' of spray.

As Vettel returns to the pits, Sato, Albers, Davidson and Liuzzi get their seasons underway.

More and more drivers take to the track, but they are merely running installation laps. The big guns - at McLaren, Ferrari and Renault - watch and wait.

That said, seven minutes into the session Lewis Hamilton leads Fernando Alonso down the pitlane, as Jenson Button crosses the line to begin what will hopefully be the first flying lap of the day.

Watching the on-board footage, for the briefest of moments, you think that Jaguar is back in F1, the green (earth) livery on the left-hand side of Button's cockpit not being quite what you expect. Elsewhere, Coulthard gets slightly out of shape, but keeps it all together.

"It's very slippery," says Button, "the white line are very slippery, and they've got some painted black lines too. Very nasty."

Ten minutes into the session, all but Massa, Raikkonen and Barrichello have made an appearance.

Being a fly away, and at such an early stage in the season - when spares are not so readily available - nobody will be wanting to take unnecessary risks. Especially when the weather for the remainder of the weekend is expected to be good.

No sooner has Button told us how bad it is than we see Barrichello go off. The Brazilian veteran keeps it all together and returns to the pits.

Good to see that the Spyker does actually look orange now and not that dreadful fluorescent red/orange we saw earlier in the year. The team shirts look good too.

Sixteen minutes into the session, Adrian Sutil posts the first time (1:50.333), with Vettel crossing the line at 52.967 moments later.

Both Ferrari drivers watch the 'action' from the pit-wall, before Raikkonen finally heads back to the garage.

Back on track, Sutil improves to 47.560, as Jarno Trulli begins his first flying lap. It was all going so well, having gone quickest in the first two sectors, then he loses it. He keeps the car well away from the barriers and continues. "Don't push too hard," he's told over the radio.

Elsewhere, Vettel goes quickest with a 46.307, only to be demoted by Trulli (45.180). However, moments later the German is back on top with a 44.911.

Alonso is back on track, though he's 0.2s off Vettel's pace in the first two sectors. The World Champion eventually crosses the line at 1:44.274 to go third, of four.