A controversial new strategy to tackle air pollution in London by penalising heavy lorries that fail to meet low emission targets has been launched by Mayor Ken Livingstone.

As of February 4, 2008, operators face a £200 charge to drive into parts of Greater London designated as a Low Emission Zone (LEZ), aimed at cutting the harmful pollution which makes London one of the most polluted capitals in Western Europe.

It is estimated that more than 23,000 heavy lorries drive through the LEZ every day and almost 3,000 fail to meet the required anti-pollution standards.

Now, those operators of diesel-engined lorries of 12 tonnes or more whose vehicles don't measure up, will have to cough up to use the London roads.

The new standards are likely to be rolled out to other vehicles in July this year to include buses, coaches, caravans and goods vans weighing more than 3.5 tons.

"This is the start of the process of gradually improving on vehicle emission standards year by year so that by 2012 when the final stage of inclusion comes, with smaller vehicles like vans and mini-buses, we will be in a position where our air quality is transformed," said Mr Livingstone.

Policing the LEZ with 75 new camera sites and 10 mobile units is expected to cost around £8m a year of which a quarter will be met by charges.