And he poked fun at Deputy Prime Minister John Prescott for his reputation as a physical bruiser.

Shropshire-educated Mr Blunkett, who has just published his controversial diaries called The Blunkett Tapes, pulled no punches in his talk at Wellington Literary Festival last night.

Asked who will be the next Prime Minister, he replied: “I can only tell you the most obvious secret in the world, which is that if there was a General Election tomorrow, Gordon Brown would walk it.”

He said he expected Tony Blair to make an announcement about his future in the New Year, adding that he was an international statesman who would be greatly missed – whether or not people liked him.

He reserved his biggest jibes for Deputy Prime Minister John Prescott who notoriously landed a left hook on a protester who had thrown an egg at him in Rhyl during the 2001 election campaign.

Asked how he and Mr Prescott get on, he said: “I don’t bump into him, he might punch me. We used to call it John’s little kiss.”

Mr Blunkett’s diaries describe Mr Prescott’s behind-the-scenes sniping following his December 2004 resignation as Home Secretary as “breathtaking” given later revelations about the Deputy Prime Minister’s affair with his diary secretary Tracey Temple.

Mr Blunkett was forced to go as Home Secretary after evidence emerged that a visa application for his ex-lover Kimberley Quinn’s nanny had been fast-tracked.

He came back into Cabinet as Work and Pensions Secretary but resigned in November 2005 after breaking the ministerial code of conduct over work he undertook as a company director while out of the Cabinet.