10 September 2010 Last updated at 07:28 ET

Mayor Boris Johnson to stand for re-election in 2012

Mayor of London Boris Johnson is to stand for re-election in 2012.

There had been speculation Conservative Mr Johnson might choose not to run in protest at the funding cuts being made by the coalition government.

He has raised concerns about the threat to the £16bn Crossrail project.

Mr Johnson, who was elected in 2008, described being mayor as the "most brilliant job in British politics" and said he was "determined to keep fighting for London".

Some of the mayor's advisers had been concerned an election in 2012 would be difficult for a Conservative candidate to win because it will be mid-term for the coalition government and the electorate will have felt the impact of the spending cuts.

Analysis

Tim Donovan

BBC London's Politics Editor

Boris Johnson has allowed some uncertainty to creep in about his intentions over the past few weeks.

Was he "haggling" with government over likely spending cuts for the capital?

Did he want guarantees over Crossrail and continuing upgrades to the Tube before committing?

Had he - as a Sunday newspaper suggested - threatened to stand down if he didn't get clearer Treasury signals?

"No", he said, to that one. Not directly to government ministers anyway.

Or was a second mayoral term something which veered from his original game plan for reaching Number 10 (or top man at the Conservative party anyway)?

Keep moving and keep 'em guessing might have been the intention.

But Johnson will be acutely aware, there is that small issue of spending cuts, whose range and depth will be all too apparent in 2012.

The mayoral battle will be the first true electoral gauge of their impact.

• Boris tries to blunt the cutters
• Has Boris got a transport deal?
• Johnson: 'I want to fight for London'

But speaking on BBC London 94.9, Mr Johnson pledged to defend London against spending cuts which he believes could damage the city's ability to generate economic growth.

He said: "I want to get the best possible settlement for London.

"David [Cameron] and George [Osborne] know the value of London and its transport infrastructure.

"London drives investment and creates jobs throughout the UK."

He added: "We have done good things but there is a big list of fantastic things we still want to achieve and two years is not enough time to achieve them."

Announcing his plans to stand for second term, he joked: "I have written a letter to the relevant person in high command for the nomination, but whether they give it to me is another question."

Caroline Roberts, regional chairman of London Conservatives, said Mr Johnson will be asked to speak at a meeting on 14 October and take questions prior to a vote on his re-selection as prospective candidate.

Asked earlier on LBC radio if his decision meant the end of his ambition to become prime minister, he said: "I have more chance of being decapitated by a Frisbee."

Labour are to decide later this month whether former mayor Ken Livingstone or former Labour MP Oona King will be their candidate to challenge Mr Johnson.

Mr Livingstone said: "Boris Johnson cannot escape the fact that he has pioneered huge cuts in London and he vigorously campaigned for his Tory colleagues to win the general election, knowing full well the economic policy they would deliver and the damage they would do to policing and transport.

"The government's cuts are his cuts."