Mr Johnson was the most high-profile candidate Johnson interview

The 43-year-old Henley MP beat off the challenge from Andrew Boff, Warwick Lightfoot and Victoria Borwick in a vote which was open to all Londoners.

Mr Johnson, an ex-magazine editor well known for his TV chat show appearance and media rows over his outspoken comments, got 75% of the 20,019 votes.

He will seek to stop current mayor Ken Livingstone winning a third term.

TORY RESULT IN FULL Boris Johnson: 15,661 votes Victoria Borwick: 1,869 Andrew Boff: 1,674 Warwick Lightfoot: 609 Profile: Boris Johnson Johnson's media scrapes

Mr Johnson won 15,661 votes, with Mrs Borwick getting 1,869 votes, Mr Boff winning 1,674 and Warwick Lightfoot picking up 609 votes.

During his campaign Mr Johnson pledged to scrap "bendy" buses and return the classic Routemaster buses to London's streets, and to "work as hard for people in zone six as in zone one".

He told the BBC he would end the "egotistical" stand-off between Mr Livingstone and London's boroughs, and stop "rabbit hutch-sized dwellings" being imposed on suburbs.

Other candidates

Opposition parties had already decided that Mr Johnson was set to be the Conservative candidate - last week Lib Dem leader Sir Menzies Campbell referred to him as the "blondest suicide note in history".

And in his speech to the Labour conference this week Mr Livingstone joked that he was proud to have been invited to give the first "Boris Johnson memorial lecture".

For all his strengths as an individual, Boris is essentially a very clever man, but ultimately a clown Tony McNulty Home Office minister

On Thursday he said Mr Johnson "proposes to add a lack of managerial competence to the Thatcherite decline and division always represented by London's Tories".

Of the defeated candidates, businesswoman Mrs Borwick has concentrated on dealing with crime, IT consultant Mr Boff proposed scrapping the congestion charge introduced by Mr Livingstone and economist Mr Lightfoot promised public service reform.

The "open primary" contest was open to all Londoners on the electoral roll who registered on a telephone hotline.

Tony McNulty, the Home Office minister, said "for all his strengths as an individual, Boris is essentially a very clever man, but ultimately a clown, and he won't put up with the sort of scrutiny that mayoral candidates do".

He described the decision to adopt Mr Johnson as a mayoral candidate as "frankly an insult to London".

A Conservative Party spokesman said the contest had "captured the interest of the public and has helped challenge voter apathy".