The campaign comes as the environmental pressure group Friends of the Earth claims air quality standards are being broken as often as once a week in some towns and cities.

Ben Elton whose novel "Gridlock" tackled this issue

It says urgent action is needed in the integrated transport White Paper if car use is to be cut.

The Transport Minister Dr Gavin Strang and comedian Ben Elton launch a Don't Choke Britain kicked off a month of events to underline the need to walk, or switch to buses, trains and bicycles, rather than use cars.

So far during 1998 levels of particulates, tiny specks released by traffic exhaust fumes, have risen above the official health standards on: 30 days in Port Talbot, South Wales, 21 days in central London and 20 days in Glasgow, Friends of the Earth says.

Ben Elton: We should think more before using the car

Summertime smog levels have broken health standards on 22 days in Thurrock, Essex.

Other places where pollution levels have broken health standards on more than 10 days so far this year include Bradford, Bristol, Bury, Cardiff, Devon (Yarner Wood), Exeter, Harwell (Oxfordshire), Hillingdon, Kingston, North Yorkshire (High Muffles), Plymouth, Redcar, Scunthorpe, Stoke, Suffolk (Sibton), Sussex Lullington Heath) and Swansea.

In most of these areas, traffic is the main source of pollution.

Pressure group support

"Friends of the Earth supports Don't Choke Britain, but ministers must realise public awareness campaigns are no substitute for tough government action to cut car use," said Friends of the Earth air pollution campaigner Tony Bosworth.

"Between 12,000 and 24,000 people die early every year because of air pollution. This needless waste of life will continue until the government acts.

"John Prescott must use next month's White Paper to announce more money for buses and bikes, tougher controls on car-based development and further cuts in road building."

The White Paper is expected to signal new parking charges, fuel taxes, and road pricing to discourage private cars clogging town centres and motorways.

But environmental groups fear cabinet differences over the document could result in a watering down of key proposals.

Last month a leaked letter from the prime minister's senior industry and transport officer, Geoff Norris to Mr Prescott disclosed these tensions.

Mr Norris, an Oxford graduate, complained the White Paper was too "anti-car" and defended the freedom which private transport could bring.

The car "is a liberating instrument for large numbers of people", he said.

But the deputy prime minister was said not to be impressed and reportedly described Mr Norris as a "teenybopper."