Barack Obama won the endorsement yesterday of three prominent Republicans, including Jim Leach and Lincoln Chafee, both of whom lost their congressional seats to Democratic opponents in the 2006 mid-term elections.

Their support swells the ranks of so-called "Obamacans" and is likely to fuel speculation that bigger names, such as Colin Powell, the former secretary of state, and Chuck Hagel, the Republican senator for Nebraska, might also endorse the Democratic nominee.