SILVERSTONE, England: Formula One's governing body has made teams a final offer, with changes to the controversial 2010 rules, in a bid to prevent the sport from tearing itself apart.

Five of the existing 10 teams - championship leaders Brawn, BMW-Sauber, McLaren, Renault and Toyota - risk exclusion if they do not sign up by a Friday evening deadline.

Should they fail to do so, there is a risk of them setting up a rival series with champions Ferrari and the two Red Bull teams also at loggerheads with the International Automobile Federation (FIA).