Red Bull crew work until 5 a.m. - long past the curfew - as Sebastian Vettel expresses unhappiness with his car.

Off the back of the German Grand Prix - the first race since Korea 2010 in which he failed to achieve a podium finish - there has been mounting speculation regarding Red Bull, and in particular Sebastian Vettel's, title bid.

In the last couple of races we have seen a number of mistakes from the German, at odds with his mature start to the season. However, in the wake of the Nurburgring race the press has joined in, suggesting that the bubble has finally burst.

A driver who wears his heart very much on his sleeve, Vettel is understood to have told the Austrian team that he isn't happy with his car here. Consequently it was stripped right down overnight in an attempt to see what might be wrong with it.

It is the first time this season that the Austrian team has broken the (2 a.m. - 8 a.m.) curfew, each allowed four exceptions.

Normally, teams will only break the curfew for serious issues such as crash repairs or a significant reliability problem. Therefore, Red Bull's move will send out signals at a time when sections of the German media clam that the youngster's season is falling apart.

Vettel goes into this weekend's race with a 77 point lead over his teammate who has scored four consecutive third places and won here twelve months ago.