Reigning world champion Jenson Button believes that there could be up to seven teams in the 2010 Formula One title hunt, the Brit adding the likes of Williams, Sauber and force India to the list of possible candidates after their performances in winter testing.

“I think there are more than four teams at the front,' he told Reuters TV. 'You've got us, Ferrari, Mercedes and Red Bull, but you've also got Sauber, Force India are not far behind, and the Williams. So it's very, very competitive, which is good to see. I'm going to be a part of it all, which is great. Going into the race with the number one on the car, what a challenge.”

Understanding testing times this winter have been harder than normal due to the fact that refuelling has been banned in 2010 and teams are therefore running with fuel tanks large enough to last the entire race distance so knowing just who was on what fuel level at any given time is virtually impossible.

Only individual teams and drivers know just how much fuel they are running with, and at this stage they won’t be giving any of that information away to anyone....