Ron Paul, the fringe Republican candidate who out-raised most of his opponents in the US presidential election, including John McCain, is to hold a joint event in Washington on Wednesday with all the other third party candidates, including Ralph Nader.

Tuesday’s announcement for an event that will also include Bob Barr, the Libertarian party candidate, Cynthia McKinney, the Green party candidate and Chuck Baldwin, the Constitution party’s candidate, has raised speculation that Mr Paul may be about to repudiate Mr McCain.