Heidfeld: No comment on BMW rumours.

Nick Heidfeld continues to refuse to talk about his much-hyped relationship with Williams' engine supplier BMW, which could lead to him becoming lead driver at the German manufacturer's 'factory' team next season.

With discussions ongoing between Williams and BMW about a possible - if unlikely - continuation next season, Heidfeld has found himself at the centre of speculation regarding the engine supplier's line-up for 2006. BMW bought into the Sauber team a month ago, and will assume full control in time to run a works team in next year's world championship. Having apparently persuaded Frank Williams to hire Heidfeld over Antonio Pizzonia this season, BMW is now tipped to prise the quietly-impressive German away from Grove to lead its attack in 2006.

Heidfeld, however, refuses to burn any bridges.

"As I've said many times before, I'm not going to comment on that," he told Reuters after qualifying for his home grand prix, "I'm in a good situation compared to last year, and I don't have any concerns. I'm part of a very good team and very happy to be on it. Anything can happen.

"For me, BMW-Williams is still one team, it should be treated like one team and it should keep functioning like one team so that we continue to improve."

If the rumour mill is anything to go by, Heidfeld could renew his partnership with former Sauber team-mate Felipe Massa next season, after BMW took an interest in the young Brazilian's performances so far this year. Massa has generally out-gunned veteran team-mate Jacques Villeneuve who, despite his assertions that working with BMW would be good, is thought likely to be bought out of his two-year contract at the end of the season.

Williams, meanwhile, continues to ponder its engine supply for 2006, with a decision expected on BMW next week. While the German company remains an outside possibility to continue next season, it is more likely that Cosworth, Toyota or Honda will form a new partnership with the Grove-based team. Toyota and Honda have effectively ruled out linking up for next season, but our spies suggest that the former may have agreed a deal for 2007 and beyond, leaving Williams to look at Cosworth's new, but untried V8, as a stop-gap option for one season.