Work to lay a hi-tech pavement designed to cut pollution has started in London.
The slabs may be laid across London
The top layer of the slabs contains titanium dioxide which helps break down nitrogen dioxide gases from car fumes.
Southampton Row in Bloomsbury, central London, is to be fitted with the paving, which designers claim has cut air pollution in Milan and Paris.
In sunlight, the titanium dioxide acts as a catalyst, breaking down nitrogen dioxide gas into nitrates which are neutralised by the concrete.
The pollutants in the air are broken down as they come into contact with the slabs through air circulation and from vehicle exhaust pipe emissions.
Italian firm Global Engineering, which developed the product, carried out a trial on a 250-metre stretch of road with an average daily transit of 15,000 vehicles in Milan in 2003.
Results showed a reduction of pollution by 60% to 70% during the rush hour, according to the firm's own findings.
Camden Council said work to install the slabs, which are grey and look like normal paving, should be completed by the end of March.
A spokesman said a year-long trial will probably be needed to evaluate whether there has been any reduction in pollution.
Councillor John Thane said: "We are testing innovative technologies such as this pollution-absorbing paving to make the borough a cleaner and more pleasant place to live and work.
"If the scheme is successful, we'll install the paving stones in other areas."