Ban on cars or £20 C-Charge

The radical "nuclear option" unveiled in his manifesto was designed to cut congestion and improve public transport.

Another serious option was to increase the congestion charge from £8 to £20 a day, penalising motorists who could take the Tube or bus instead. Launching his mayoral-campaign in Brixton, he vowed to scrap the western extension zone, which runs from Marble Arch to Notting Hill, if he defeats Ken Livingstone in the elections held on 1 May.

Mr Paddick told the Standard today: "We have got a dilemma here. The streets of London are not built to allow everybody who wants to drive in central London to drive. That is the essence of the problem. Congestion is back at the same level it was before the congestion charge was introduced. One radical solution is to ban all cars from central London. We need to consider that. It's a nuclear option. It doesn't matter how rich you are - you just can't drive. It's a very swift way to make sure public transport improves.

"The other way is to say you can't remove people's right to drive if they want to - but if they choose to drive they have to pay for that privilege."

He floated the idea of reducing the £8 weekday charge for essential journeys - and awarding every driver registered at a London address with six passes a year allowing them to enter central London for free. "I would want to differentiate between people who have the choice of making their journey on public transport against those people who have no choice at all," he said.

Mr Paddick suggested he would shelve Mr Livingstone's plans for an emissions zone to crack down on vans and lorries going into central London.

"I'm not a great fan of white van man but that is the sort of person who is going to be hit by that emissions zone. It's going to cost millions of pounds and make very little difference," he said.

He promised to improve the reliability of the Tube and bus services, bring in unlimited travel for one hour on pay-as-you-go Oyster cards and consider free travel for students.

The former Met officer, who oversaw a dramatic fall in crime in London during his time as borough commander, pledged to cut crime in London by 20 per cent over the next four years. He even promised he would stand down after one term if he failed to meet his target.

He said he will take personal responsibility for reducing killings in the capital by chairing the Metropolitan Police Authority. "Ken Livingstone said he cannot do anything about gun and knife crime. Boris Johnson has admitted he doesn't have the experience to deal with it. It's time for someone who can stop the slaughter on our streets," he said.