Gloves off ... Boris takes on crime

He promised to use measures in the Proceeds of Crime Bill to allow the Met to keep confiscated cash rather than handing it over to the Home Office.

The Tory candidate said he would fight off any attempt to block him by Home Secretary Jacqui Smith, whom he wants to meet to discuss the plans.

However, the Met already gets back 50 per cent of all assets seized, irrespective of crime, netting them an extra £1.4 million last year.

Mr Johnson told The Sun: " Everyone I meet in London is worried about crime on the streets, and they know it stems from drugs. These crooks are making a fortune by peddling drugs, using the cash to buy luxury homes, flash cars, jewellery, plasma TVs and whatever else. London police should know that when they seize such assets they will be allowed to use it to the benefit of Londoners."

The money would fund a range of measures including more drug rehabilitation schemes.

Mr Johnson blamed drugs for feeding gang culture, which has led to a series of stabbings and a rise in gun crime in London. He put tackling crime at the heart of his manifesto after Londoners made it clear it was their top priority for the Mayor. However, Ken Livingstone said the Met already gets money back from drug seizures. He said: "We're always arguing with the Government we should keep more of it and I'm delighted Boris has seen our point of view."

Liberal Democrat candidate Brian Paddick denied reports that he would take a job from Mr Johnson if the Tory was elected. There had been rumours Mr Johnson was prepared to offer him the chair of the Metropolitan Police Authority, even though Mr Johnson has said he would take the role himself so he could better lobby the Government.

But the former police officer said: "I could not work with Boris Johnson. Ken Livingstone and Boris Johnson are as bad as each other and I would never serve in either of their administrations."

He said the thought of having Mr Livingstone as his boss "sends shivers down my spine".

Mr Paddick refused to say who he would endorse with his second preference votes, which could swing the election, merely suggesting it would not be either of his two main rivals.

He said: "The way democracy works is this - you have different candidates and they try and convince the electorate that they are the best candidate.

"As far as who people vote for after that candidate, that's a matter for them."