Mayor admits that Johnson could win

He even advised his Tory rival to oversee a "graduated transition" should Mr Johnson win the mayoralty.

Mr Livingstone, who was launching his overall manifesto today, spoke frankly about a possible defeat and the reality of life after City Hall.

The Mayor would immediately begin work on his autobiography.

He said he was trying to focus on winning but admitted that if he lost he could take up Mr Johnson's afterdinner speaking engagements.

Mr Livingstone revealed what he would be doing following any defeat on 1 May: "If I don't win, come 6 May I will be taking the kids to school and starting a book on my last eight years as Mayor."

Previously, he had consistently refused to comment on what he might do if defeated, but he dropped his guard yesterday on the campaign trail in Lewisham, even providing some hints on how a new mayor should behave.

"My advice would be don't rush to make rapid change, try to take your time to talk to people and listen, and actually organise a more graduated transition," said Mr Livingstone.

"Because someone who comes [in] with 'slash and burn' might then find after six months that was a big mistake. So I'd take your time.

"Boris, because he has never been a council committee chairman or chair of a local authority, or involved in any other local government, would still have a lot to learn even after the election. I was lucky I had 30 years' experience in local government before I got in. He shouldn't rush."

He added: "If I lost there would be a vacancy on the after-dinner speaking circuit so we would really just be swapping jobs."

No publishing deal has been negotiated yet for his autobiography.

Although those close to the Mayor believe he is just ahead or neck and neck in the polls, there are major fears among Labour activists about getting their supporters out to vote.

The Evening Standard's YouGov polling suggests Mr Johnson has maintained his lead and is set to win next week. Critics will suspect that talk about losing is a ploy by Mr Livingstone to galvanise Labour supporters into voting for him.

At his manifesto launch today in Wood Green, the Mayor unveiled his complete policies on transport, crime, housing and other issues.

He emphasised the winning of the Olympics and the 7/7 terror attacks the following day as the reason he should be re-elected.

Mr Livingstone was joined by George Psaradakis, the driver of the No 31 bus bombed in Tavistock Square, who said: "There are some moments in your life you never forget-The terrorist attack of 7 July, when the bus I was driving was bombed, was one of those moments.

"Ken Livingstone gave London the leadership our city needed that day. He united London when it faced its greatest threat."

The Mayor stressed he had not given up in the race. "People say he's tired, he's old, he's been around too long. But I feel we are only just beginning."

He said the successful Olympic bid was down to "three years of detailed planning", and that the calm response to the terror attacks was another example of careful planning.