Ken: I'm the man to deliver better transport

The Mayor said plans to build Crossrail, the East London Line extension and other improvements could only be safely carried out if he was reelected.

He attacked his rival Boris Johnson, saying Londoners risked "not only a transport but a financial disaster" if the Tory candidate was elected in May.

Launching his plans in Stratford, Mr Livingstone warned of huge fare increases if the projects were mismanaged-He said: "The biggest task confronting the Mayor over the next four years is to successfully deliver the huge transport projects that are now under way in London because these are the key not only to moving around the city but to the entire finances of London.

He added: "If schemes like Crossrail, the bringing of local rail services under London's control with London Overground, Tube modernisation and the management of our buses go wrong, they are so large they will create not only a transport but a financial disaster for London with huge rises in fares and business rates."

Mr Livingstone set out plans for:

Taking over the operation of the Southern trains franchise to complete his plan for an overground rail orbital by linking the extended East London line to Clapham junction via West Croydon;

A single bus route down Oxford Street and, after 2012, a tram for shoppers;

Giving injured Army veterans free travel;

A major investment in clean vehicle technology by putting 500 hybrid buses on the streets by 2010 and all new buses being hybrid by 2012 at the latest;

Doubling the number of countdown signs at bus stops to 4,000 with a new state-of-the-art GPS tracking system;

A new congestion charge system so drivers can have payments automatically debited when entering the charging zone, avoiding fines.

Central to Mr Livingstone's launch was his claim that a so-called "£100 million-ayear error" in Mr Johnson's bus plans showed he lacked competence. His sustained criticism of the costings for a new Routemaster bus with conductors indicates how seriously he has taken the threat of a Tory victory.

Mr Livingstone said: "We can't have that sort of mistake repeated on the scale of the projects that we are seeing now."

The Livingstone campaign believes it has struck gold with the bus figures row. But the Tory candidate has stuck by his claim that replacing bendy buses with the Routemaster would cost £8 million a year. He accused the Mayor of being "negative, defeatist and misleading".

Mr Livingstone has already promised an orbital rail service around London. He is now in talks with the Transport Department to take over parts of the Southern Railways franchise, to extend the London Overground service to include trains from Victoria and London Bridge.

Transport policies would go "hand in hand" with environmental ones, such as the low emissions zone and the £25 charge for gas-guzzling cars, he said.

He would encourage councils to bring in more 20mph zones around schools and on residential streets while replacing speed bumps with camera technology. Mr Livingstone said: "One of the advantages of using public transport every day myself is that I see the transport system as Londoners experience it.

"This is why ... I have been committed to better public transport for Londoners and why, as Mayor, I have devoted so much time and energy to getting the transport improvements Londoners expect."

Liberal Democrat candidate Brian Paddick said his rivals were both wrong and had been distracted by "bickering" instead of looking for real solutions.

He said: "What we need is a clean, fast and reliable mass transport system that can carry twice as many people as the bendy bus: London needs trams."