HARROW is working with 27 other London boroughs to improve the capital's air by clamping down on vehicles which emit dangerously high levels of pollution.

New legislation allows local authorities to stop vehicles at random, test their emissions at the roadside, and fine the drivers of those that fail to meet legal standards.

Any vehicle being driven in the borough can be tested in the scheme, which began this week, but it is expected that only a minority of older or badly maintained ones will fail.

A uniformed police officer will stop vehicles and a qualified vehicle tester will check their emission levels, which takes only a couple of minutes.

The test checks the levels of pollutants including carbon monoxide, carbon dioxide and hydrocarbons.

If your vehicle is tested and fails to meet the standards required, you may be issued with a fixed penalty notice, which would require you to pay a £60 fine. This can be reduced to £30 if the vehicle's fault is corrected to bring emissions within legal levels within 14 days.

Vehicles should be serviced at least twice a year by a professional mechanic. An emissions check is included as part of the MoT.

A council spokesman said: "All vehicles emit some level of pollution, but older and poorly maintained vehicles are generally the worst.

"If your car's engine is not running efficiently, it may be emitting more pollution than it should. But vehicles that are in good working order should pass the test."

Gareth Llywelyn Roberts, the council's chief environmental health officer, said that poor air quality had been linked to a number of health problems, particularly in the elderly or the very young.

"Harrow is prepared to use the legislation available to local authorities to clamp down on drivers whose vehicles cause pollution, and in turn improve air quality in the borough."