Labour moved on Sunday to disown Derek Draper, the high-profile activist, as it sought to minimise the fallout from revelations that he had discussed an anti-Tory smear campaign with Damian McBride, a Downing Street aide.

Party officials insisted that Mr Draper’s website, LabourList, was not owned by the party – in spite of it publishing submissions by stalwarts such as Alastair Campbell, John Prescott, Lord Mandelson and Harriet Harman.