If the BMW WilliamsF1 team wants to continue their partnership with BMW there public comments from members of WilliamsF1 management will do little to ease the tension that appears to exist between the two parties.

But for team boss Frank Williams the relationship that has existed between his team and BMW has been one of the most hostile in terms of engine suppliers, and WilliamsF1 has had several major car manufacturers supply them engines over the years.

In an interview for the British Autosport magazine Williams said: "Our partnerships in the past with Renault and Honda have been more successful and co-operative. You never had this constant finger-pointing. We do not constantly ask why BMW had some 150 engine failures in 2000 alone."

The strain has not been helped by the constants rumours that BMW has been considering buying the Sauber team, or at least to supply the Swiss team with engines starting in 2006.

Another member of WilliamsF1 management has also joined Frank in voicing his dissatisfaction with the situation with engine supplier BMW. In an interview for the Italian media Head states that many of the problems that exist are of BMW's doing and to blame the WilliamsF1 team for all of these was going too far. He also made it clear that the WilliamsF1 team had already been discussing the future supply of engines from other manufacturers if BMW and WilliamsF1 part company.

Head said in Italy's Sport Auto Moto: "We adopt the same strategy as [BMW], and our doubts are especially about the way they handle the engine's power."

In regard to whether WilliamsF1 was taking to other suppliers Head added: "Obviously yes, since BMW decided to talk publicly about their dissatisfaction in their relationship with the Williams team. This is something I personally consider to be extremely unprofessional.

"I haven't been very well impressed by this attitude, which is when a constructor pretends that every problem comes from the car and not from the engine. When the car always starts [races] badly, in my opinion it's more likely that it depends on the engine's control systems rather than the car's.

"Unfortunately our partner chose to tell people they are perfect while accusing us. This is honestly something which, besides being very unprofessional, shows very little character. So, with this situation ... I admit that yes, we have spoken to a certain number of people."

Head spoke out about how BMW's Motorsport Director Dr Mario Theissen behaved, saying that it was  a dishonest approach.

Head added: "BMW say that they have the best of everything, but it's not true," Head said. "In my opinion, we should work like a united family, but instead this doesn't happen at all. In the last three years we've developed a starting system together - 50% ourselves and 50% them.

"But when the car starts badly they are very ready to accuse; they never talk about 'our engine' or 'our clutch' or whatever. I think this is Mario Theissen's approach, and it's a dishonest approach. We must live with this way of behaving of theirs, but we can't act the same way."

But both Frank Williams and Head have also said that they would not rule out continuing with BMW, even if they do buy Sauber.

Head said: "We would have to look at the situation and evaluate it closely, but we'll certainly pay great attention at every other option. Having said that, if it will be available it's a possibility."

In response to the comments coming from the WilliamsF1 management BMW's Dr Theissen has said in the 'Netzeitung' publication that 'there's no problem.

Theissen said: "We continue to work absolutely professionally together."

Whether the WilliamsF1 team will have the use of BMW engines in 2006 is uncertain but there is a contract which says that BMW will supply the WilliamsF1 team until 2009.