Red Bull to introduce major upgrade

The changes, which will include a new nose, engine cover and rear diffuser as well as modifications to the car's wheel-base - which has been back through the chassis - are believed to have given the car a significantly look.

The team's drivers have played down the changes, adding that they would prefer to comment once they have tried the modifications on track.

"We've got a couple of new things on the car, which you will be able to see from the outside, we hope they work - that's why they put it on the car," said Sebastian Vettel. "But we will have to prove it on Friday, Saturday and Sunday. So let's see.

"Our target is to win, it has been for the last couple of races and it is here so we have to beat Brawn. Not just match them, then it is quite tight, but I think this circuit suits our car.

"A lot of fast corners and medium speed corners, so let's hope the few bits on the car make a difference, and we will finally make the breakthrough."

Vettel's team-mate Mark Webber added: "We hope it's worth a few tenths... one or two tenths maximum."

In a press conference on Thursday, pre-race favourite Button recognised that Red Bull could prove a big threat to his hopes of a home win this weekend: "I have heard that Red Bull have got a big upgrade, I don't know how big but I hope it is not too big. So we will see."