Ken Livingstone has rejoined the Labour Party and will now seek to become the party's official candidate in London's mayoral elections.

Labour's National Executive Committee yesterday backed his return by a margin of 22 to two.

Even John Prescott, a notable critic of the mayor, voted for his readmission, but is reported to have told the meeting that he was "holding his nose" as he did so.

Tony Blair admitted that his predictions that Livingstone would be a "disaster" for London had turned out to be wrong.

"The truth is, he has not been as I thought he would be. When people say to me, 'Have you changed your mind on this?', the answer is 'Yes, I have'," he said.