Johnson presents crime, housing and transport as his priorities

Boris Johnson will launch his drive today to oust Ken Livingstone as Mayor of London with a pledge to tackle knife crime and the capital's growing gang culture.

Following an opinion poll showing him neck-and-neck with Mr Livingstone among voters, hopes are growing among senior Tories that Mr Johnson can capture the capital for the party.

Some are nervous that their outspoken candidate's ability to attract unwelcome controversy could derail his campaign. Others are worried that his relatively low profile in recent months reveals a lack of appetite for the forthcoming battle.

But Mr Johnson, still best known to many voters as a gaffe-prone occasional presenter of Have I Got News for You, will attempt to answer his critics with a series of detailed policy announcements designed to add up to an alternative manifesto for London. With the numbers of fatal stabbings of teenagers increasing by 50 per cent last year, he will put law and order at the heart of his campaign, setting out a plan for cutting levels of knife crime and stemming gang violence.

He will argue that inner-city communities face a spiral of decline if their streets are unsafe, with families moving, shops closing and investment going elsewhere.

Today's plans to combat crime will be followed by proposals for rejuvenating public transport, tackling the shortage of affordable housing and ensuring the 2012 London Olympics stay on budget. They will build towards a manifesto due to be published in February. A month of promoting its key messages will be followed by six weeks' intensive campaigning in the run-up to the poll on 1 May.

Mr Johnson's campaign is being bolstered by Lynton Crosby, the renowned election strategist who masterminded four successive victories for John Howard, the former Australian prime minister. He will take charge of Mr Johnson's main themes and polling.

A YouGov poll for ITV's London Tonight put Mr Livingstone on 45 per cent support and Mr Johnson on 44 per cent. Brian Paddick, the Liberal Democrat candidate, trailed with 7 per cent. A series of bets on Mr Johnson has led the bookmaker Ladbrokes to cut his odds to 6/4. Mr Livingstone is still odds-on to win at 4/7, but the gap between them is narrowing.

Mr Johnson's tactics since he won the Tory nomination at a primary in September have surprised some party MPs who had expected an immediate flurry of colourful attacks on "Red Ken". Instead, he has held more than 50 meetings away from the cameras with councillors, voluntary groups, transport officials, police and other key groups of Londoners.

Tory critics said the time had now come for Mr Johnson to change gear and start proving to doubters that he is a serious politician. One MP said: "There is a feeling that he needs to crack on and I think he will do so." The Johnson team retorts that work has begun to differentiate their man from Mr Livingstone and insists it was essential for him to undertake intensive research on London's problems before setting out his stall to voters. A spokeswoman for Mr Johnson said: "When we won the primary, people came up to us and said 'well done' and 'now do your homework'. We know that if we get one statistic wrong we will be punished."

She said Mr Johnson had been working round the clock to prepare his campaign for the mayoralty and fulfil his commitments as the MP for Henley.

Although there have been regular contacts between the Johnson team and Conservative Central Office, it has not yet been decided how great a role David Cameron and other shadow cabinet members will play in the campaign.

Mr Johnson's spokeswoman insisted he would not try to play it safe for fear of being accused of blundering. She said: "Boris is Boris. If we tried to change him one iota we would be doing the nation a disservice. "He will say bold things. It's refreshing because politicians are so boring these days."