Ken: Get Crossrail right or it could ruin London

The Mayor said the long-delayed highspeed link between the City and Heathrow would help safeguard the capital's status as a financial powerhouse.

But he added this would require the payment of some of the highest public-sector salaries in London to keep the project on track for completion in 2018.

Mr Livingstone, addressing an Evening Standard debate on how London can stay ahead as a great world city, said: "Probably the most important single issue facing the next mayor is getting that right. If we get it wrong the scale of that project is enough to bankrupt London.

"We will bring people in that will be earning more than anybody else in this room in order to deliver that project on time and to budget." The Mayor helps oversee the construction of Crossrail through Transport for London, which currently appoints half the project's directors.

The rail scheme will come under full TfL control once the Bill establishing it gets royal assent. Mr Livingstone was appearing alongside Labour MP Diane Abbott, Financial Times editor Lionel Barber and LBC radio presenter Nick Ferrari at last night's debate.

Click here to watch video highlights of the debate

The Mayor's proposal to increase the congestion charge to £25 a day for vehicles with the highest emissions sparked frequent protests from the audience.

Some speakers were concerned about its poor environmental benefits - a point the Mayor conceded - and the fact that congestion inside the zone could worsen if drivers switched to small-engined band B cars, which will be made exempt.

Mr Livingstone said Londoners could again use the mayoral election to show their support or opposition to his highest profile policy. He said he and Green candidate Sian Berry would support the £25 congestion charge in the 1 May poll while Tory Boris Johnson and Liberal Democrat Brian Paddick would propose alternatives. Mr Livingstone said: "I went into the first election saying I would do the first congestion charge.

"I went into the second saying I would do the [western] extension. I'm going into this one saying I will do the £25. This isn't some wicked thing where I spring a surprise.

"It's a congestion charge and that is the primary reason for it. We have finessed it to have a pollution dimension."

LBC presenter and unashamed motorist Nick Ferrari said the £25 charge smacked of class war by a Mayor who had never learned to drive - and therefore couldn't understand how so many Londoners loved their cars. He said: "Red Ken has gone green - that is, green with envy, because he doesn't like people who are doing well."

But Mr Livingstone hit back - and vowed to drop the exemption for band B cars if too many flooded in.

He said: "You have to ask yourself, would somebody choose to drive into central London if they didn't have to? I would say you would have to be mad to drive into central London if you didn't have to." The panel agreed on the importance of maintaining the strength of the City, and there was concern at the risk of driving away "non-doms" who risk being penalised by changes to the tax system.

Financial Times editor Lionel Barber said London had deluded itself into believing it was the best city in the world 18 months ago, on the basis of some cutting edge cuisine.

He said: "Compared to New York, London comes a distinct second. The Tube is a disgrace. It's maybe not as safe as some Tubes around the world. It's overcrowded. It doesn't work, and it's Victorian in the worst sense of the word."

To read what the panellists said, click here
Click here to watch video highlights of the debate

To apply for tickets to the next debate - Who should be the next mayor of London? - featuring Ken Livingstone, Boris Johnson and Brian Paddick click here