Video: Londoners tell Times Online who gets their vote

Ken Livingstone today used the last day of campaigning before the elections for London Mayor to launch his most vicious attack yet on Boris Johnson, deliberately attempting to play on public uncertainty over his rival's credibility.

With polling due to open tomorrow morning, the mayor announced he had sent postcards to a million Londoners which say: 'Don't vote for a joke. Vote for London' and said the Conservative candidate would be a "celebrity mayor", unable to take tough decisions.

Standing with a group of Labour supporters at West Ham's Upton Park stadium next to a giant poster echoing the message, Mr Livingstone explained: "It’s not an election for the host of Have I Got News For You or Celebrity Mayor. It’s about who is best placed to run an £11 billion budget every year.

"The problem is Boris has been managed and people haven’t been able to get to him. It’s hard to know what Boris really believes.

"The abiding image most Londoners have from television debates is of Boris Johnson not being able to answer the questions."

Mr Livingstone's highly personalised attack was designed to play on what polls show are the public's most deep-seated fears about his rival - that the former Spectator editor and newspaper journalist is too gaffe-prone, lacks seriousness and heavyweight political credibility.

A poll by the Evening Standard newspaper, which has supported the Tory candidate, put the MP for Henley, Oxfordshire, 10 points ahead, although other polls say it is much closer.

Mr Livingstone said he thought the two were "neck and neck" and predicted a record turnout. Predicting second preference votes could decide the outcome, the Mayor launched a direct appeal to supporters of Brian Paddick, the Liberal Democrat candidate, to put him as their second choice.

"There aren’t many Liberal Democrats who could go back and read Boris’ articles and think ’That’s what I agree with’," he said.

Mr Johnson, who is today emailing 500,000 Londoners to encourage them to vote for him tomorrow, pledged to tackle gun and knife crime and put more police on the transport system, as well as protecting green spaces in the capital.

"Tomorrow you have a choice: between new policies and fresh energy from a new Mayor in City Hall, or more of the same from a tired, out-of-date administration that is beset by allegations of sleaze," he said, visiting voters in Tottenham.

"I am optimistic about London’s future, and believe we can make a London a greater place to live in. If you share my hopes and aspirations for our city, please come out to vote tomorrow."

Voting in London coincides with council elections all over the country, with some polls saying Labour is heading for a large defeat as part of a national backlash against Gordon Brown.

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