Boris is the Mayor

The Tory MP ended Mr Livingstone's eight-year reign at City Hall to round off a disastrous 24 hours for the Labour party.

After a drawn-out count, which ended at midnight, Mr Johnson emerged triumphant with 53 per cent (1,168,738) of Londoners' votes compared to his rival's 47 per cent (1,028,966).

The result was exactly as predicted in a YouGov poll for Thursday's Evening Standard which put the Tory candidate at 53 per cent, six ahead of Mr Livingstone with 47 per cent.

In his victory speech at City Hall, Mr Johnson paid tribute to his defeated Labour rival.

He said: "For you, Ken, Mayor Livingstone, I think you have been a very considerable public servant and a distinguished leader of this city. When we both have that drink together that we so richly deserve, I hope we can discover a way in which the mayoralty can continue to benefit from your transparent love of London."

He suggested that winning City Hall would give him an opportunity to prove that the Conservatives were once again ready to govern.

"I do not for one minute believe that London has been transformed over night into a Conservative city but I do hope it does show that the Conservatives have changed into a party that can be trusted."

The new mayor told the people of London that he would work 'flat out' to earn their trust.

"We have a new team ready to go to City Hall. Where there are mistakes we will rectify them, where there are achievements we will build on them, where there are neglected opportunities we will seize on them and we will focus on the priorities of the people of London."

He told the people gathered in the chamber: "Let's get cracking tomorrow and let's have a drink tonight."

As well as delivering a bitter blow to Gordon Brown, Mr Johnson's triumph signals the end of an era in London politics dominated by Mr Livingstone for nearly 30 years.

A tearful Mr Livingstone paid tribute to all the Londoners who had voted for him over the years and all the members of staff - from the chief executive of City Hall to bus and tube drivers - who had worked with him.

The outgoing mayor also took full responsibility for his defeat and refused to blame Gordon Brown.

"I am sorry I couldn't get an extra few percentage points that would have taken us to victory. The fault for that is solely my own. You can't be mayor for eight years and, then if you don't have that third term, say it was sombody else's fault."

Mr Livingstone said that being mayor had been "the most amazing experience" and made a surprise offer to help Boris Johnson.

"I can give you my assurance I will do all I can to help the new administration in any way it seeks. But in whatever role, I will continue whilst I live and breathe in this city, to love this city and to work to make it better."

Mr Johnson won 42 per cent of first preference votes, while Mr Livingstone won 36 per cent.

Liberal Democrat candidate Brian Paddick was third on 10 and was knocked out. The Conservative candidate then crossed the 50 per cent finish line with 124,977 second preference votes, ahead of Mr Livingstone's 135,089.

David Cameron was among the first to congratulate his new Mayor of London for turning the capital into a Tory city for the first time in a generation.

The turnout for the mayoral election was 45 per cent which was eight per cent higher than that of 2004 when only 37 per cent turned out to vote.

All of the 14 Assembly constituencies were held apart from the suprise gain for Labour of the Conservative seat of Brent and Harrow.

After a night of losses in the local elections across the country, the Prime Minister was under intense pressure to carry out a snap Cabinet reshuffle to relaunch his Government.

If Londoners vote Tory in similar numbers at the next general election, crucial Labour marginals will tumble and Mr Brown faces being turned out of Number 10.

The BNP party gained its first seat in the history of the London Assembly. Dagenham councillor Richard Barnbrook, who has pledged to end all further immigration, was among the 25 members elected.