Former Labour MP Brian Sedgemore, who defected to the Liberal Democrats, attacked Tony Blair in an address to the Oxford Union on April 26.

Mr Sedgemore said: "To my former comrades I say sorry, but all nightmares have to end. Tonight I'm renouncing Tony Blair, the Devil, New Labour and all their works."

Earlier, Mr Sedgemore, who stood down as MP for Hackney South and Shoreditch at the election after 27 years at Westminster, had urged voters to give Tony Blair "a bloody nose" on May 5 and follow his lead by backing the Lib Dems.

He also warned that other retiring Labour MPs are planning to quit Labour after the election, although he refused to name names.