It is claimed that a decision on which manufacturer(s) will supply tyres for the 2011 Formula One World Championship season is imminent, with some saying an announcement could be made this weekend.

At the time of Bridgestone's announcement that it intended withdrawing from F1 at the end of 2010, attention was fully focussed on the forthcoming season. Consequently, while a few possible replacements were mentioned, little serious thought was given as to who might step into the breach.

While Korean manufacturer Kumho was mentioned, having first expressed an interest in entering F1 way back in 2004, it was widely assumed that Michelin, considering the circumstances in which it left the sport in 2006, would not be interested in returning.

Yet, now, we have Pirelli, Michelin and Avon expressing serious interest and continued speculation that, if the circumstances are right, Bridgestone could remain - a move given further substance at the weekend when the head of Bridgestone Europe made a surprise visit to the Grand Prix.

McLaren boss Martin Whitmarsh believes that a decision could be just days away but admits that cost will be an issue, ironic when one considers how important those four bits of rubber are to the sport.

"There are four proposals that appear to be out there and maybe there's another couple as well," he told Reuters. "I think we are running out of time so we are going to have to make a decision quickly.

"We have got to try and balance the different philosophies," he continued. "Some of the bigger teams want the lowest technical risk and some of the smaller teams are prepared to accept technical risk in exchange for a substantially better commercial deal. The teams are trying to be sensible and mature and balanced about that but we can't hide the fact that there are those who are fighting for survival that just want tyres for free or whatever and will live with the risks. The established teams are prepared to pay perhaps a little bit more of a premium."

Referring to Michelin's call for multiple suppliers, a move that would see the return of the tyre war, Whitmarsh added a note of caution.

"If you use multiple suppliers, it has got to be controlled in terms of testing and development," he said. "Philosophically, Michelin want competition and want the opportunity for competition. I think they are very pragmatic in their support of F1 and accept they may enter in the short term as a sole supplier by default, but welcoming competition thereafter."

Speaking in the wake of Sunday's Grand Prix, Mercedes' Nick Fry confirmed that efferts are still being made to persuade Bridgestone to remain in F1, even though the Japanese manufacturer insists that there will be no u-turn and that it follow Honda and Toyota out of the sport.

However, Fry admitted that a decision needs to be made soon. "I think we've got to come to a decision in the next 10 days or so," he said. "The encouraging thing is that we are in a massively better position than we were three or four weeks ago when it looked as though we might only have one opportunity open to us.

"Now we've got three and I think discussions are still going on trying to persuade Bridgestone that they might like to stay. Even if they don't there's three options open to us and I think any of those three could provide a suitable tyre."

As Pitpass pointed out yesterday, McLaren test driver Gary Paffett's admission that McLaren will begin testing its 2011 car this week indicates that the Woking team must know something the rest of us don't, certainly when Michelin and Pirelli have both said that they wish to increase wheel diameter from 13 to 18 inches.