London may introduce a charge on polluting diesel vehicles that enter the centre of the British capital, in a bid to meet EU rules, mayor Boris Johnson said on Tuesday.

The fee would be on the lines of the "congestion charge" for all vehicles entering central London, which is currently �11.50 a day ($19.50, 14.50 euros), a spokesman said.

The plan is part of a new Brussels-compliant Ultra Low Emission Zone (ULEZ) being introduced in London from 2020, which Conservative Johnson announced last year.

"You have to have a charge that makes a difference. We've got to get our air quality better," he told BBC radio, adding that "the price for that is up for consultation".

"We've got a big air quality problem in London, like many other big cities around the world, we've got people dying prematurely, we're in breach of European guidelines."

A spokesman for Johnson told AFP that as part of consultations on air pollution "one option is to bring in a charge for high polluting vehicles on similar level to the congestion charge."

Only diesel vehicles meeting new EU emissions standards will be exempt from the fee, while petrol cars registered before 2006 will also have to pay, officials said.

London's congestion charge was introduced in 2003 by Johnson's predecessor Ken Livingstone in order to ease pressure on the city's roads.

The emission zone is aimed at getting London two-thirds of the way to meeting strict air pollution targets set by Brussels.