BMW dismisses Heidfeld exit rumours

Stories in the German press have suggested that the 32-year-old is set to be replaced at the end of his contract, but Theissen says that no decision will be taken on the team's driver line-up before September, adding that rediscovering competitive form was BMW's current priority.

"First of all, I haven't read it," said Theissen. "And even if I had read it I wouldn't make any comment and wouldn't react to it. As far as our present driver line-up is concerned I am not prepared to say anything negative.

"At the end of the day we can only talk about that when we are fast again and our driver line-up for the next year is traditionally decided in September."

Theissen believes that BMW, whose cars showed disastrous form in Monaco with neither Heidfeld nor Robert Kubica making it past Q1 in qualifying, is a victim of its high level of achievement so far in F1.

"In top sport you have waves of success and we've always been clear about that," said Theissen. "The big problem for us is that for the last three years we have shown a continual upswing in results and this is our first real step back - and we have to gather ourselves and work through it. And that is what we are busy doing.

"Our board of directors see it as that. We are one team and they accept it, and they realise it. We just have to work for it."

Theissen also revealed that BMW remains 'open' over whether to continue to use its KERS system in the 2009 car. "We will see next weekend," he said. "At the moment we are looking to see what the problem with our overall situation is.

"For me everything is open. We will drive the race and then analyse where we stand and then decide how to continue."