Williams have committed to Formula One beyond 2007 after signing an extension of the Concorde Agreement.
Williams had been part of a manufacturers' group threatening a breakaway championship, but they joined Ferrari, Red Bull and Midland in signing up to an extension of the current arrangement with Bernie Ecclestone.
Today's news gives Formula One a 50-50 split between Ecclestone's series and the manufacturers' group who are demanding more money and a greater say in the way the sport is run.
A Williams spokesman revealed an improved offer from Ecclestone after weeks of negotiations had finally persuaded Frank Williams to agree.
