As BMW confirms that it is to enter F1 in its own right, having bought a major slice of Sauber, the big question is, whose engines will WilliamsF1 use in 2006?

Speaking at today's press conference in Munich, BMW's Mario Theissen admitted that buying into the Grove outfit was never really an option, since the German manufacturer wanted a majority shareholding, something that Frank Williams and partner Patrick Head were never likely to agree to.

"The majority share in Williams has never been in the offing and we have never discussed it," Theissen told journalists. "The step we take now makes sense only if it is a perfect match, which means we can weld two teams together that they form a unified team in the future. This came about through our talks with Sauber and the result is the decision we announced today."

However, the German manufacturer is keen to retain its relationship with the English team, and was at pains to stress that should WilliamsF1 wish to continue, it would have parity - engine-wise - with BMW's own team.

"We had successes, with Williams," said Theissen, "we were stimulating each other and we are well prepared for the future and we want this success, we want this success this year without any restriction, we want to win races during this season and we would be very happy if Williams will use the BMW engine for next season and this will be the topic of the next talks that we will have.

"If we give engines to a second team the engines will have BMW stenciled on it," he continued, "they won't be second rate or second class engines, we want to develop one type of engine, there is one ambition behind this but does not make sense to have two types of engines during the season so a second team will use and operate the same engines as the first team," he added.

WilliamsF1 has yet to react, consequently there is much speculation as to what the English team might choose to do.

BMW will be under no illusions, it is not going to be able to build a winning team from scratch, therefore a continued relationship with WilliamsF1 would be to the German manufacturer's advantage.

However, in the long term, WilliamsF1 will need to look for a new partner.

There has been talk of WilliamsF1 re-establishing its relationship with Honda, with which it enjoyed success in the 1980s, however BAR's 45% stake in BAR means that this is unlikely.

There has been talk of Toyota supplying engines to the Grove team, and re-badging them as Lexus.

On the other hand, Frank Williams could opt to return to where it all began, and place a Cosworth in the back of the FW28.

Speaking at Indianapolis on Friday, Frank Williams hinted that a decision may already have been made. Talking about 'Independent teams', Williams said: "Are we an independent team? We certainly are. We've managed to get through merit a freebie engine but next year, maybe, we have to pay engines."