Drivers welcomed spot checks by Oxford City Council officers today, aimed at cutting air pollution in the city centre.

Motorists will be hit by £40 fines - and ultimately could face court action - if they leave their engines running for just a matter of minutes.

Ian Wright, public health manager for the city council's environmental health department, toured the city centre with fellow council officer Tony Nanton for the first day's enforcement today.

They carried out checks in Queen Street, Magdalen Street, Cornmarket Street, George Street and outside Oxford railway station, off Botley Road.

No fines were handed out, but Mr Wright said the council had a policy of warning drivers before issuing them with a ticket.

He added: "If we spot a driver whose engine is running unnecessarily we approach the driver and warn them to turn it off.

"If they refuse, we will issue a fixed penalty notice for £20, and if they do not pay within 28 days that goes up to £40, and then we can go to the county court to get a court order if they still won't pay."

After checking about 20 vehicles, Mr Wright said: "We're very pleased with the results of this initial spot check because the vast majority of drivers already know what we are doing and are supporting us by switching their engines off as soon as they can."

Mick Rutt, an Oxford Bus Company driver, waiting in George Street for passengers to board the number four to Rose Hill, switched his engine off after one minute.

He said: "If we're at a terminus for longer than a minute we switch off.

"Our controllers are watching us and we could face disciplinary action if we don't go along with it."

Ray King, a taxi driver for Radio Taxis, parked in Gloucester Green, was waiting for passengers with his engine switched off.

He said: "I always switch off my engine as a matter of course when I am waiting because I do not want to add to the pollution."

Window cleaners parked in George Street with the engine running were warned by Mr Wright and Mr Stanton about the new regulations.

They told the officers they were not aware of the change and immediately drove off.

The Town Hall has been equipped with powers to fine motorists for engine idling since 2002 - but enforcement only started today.

It is hoped the new get-tough approach will slash nitrogen dioxide levels, which in some streets are more than double the Government's air quality standard of 40mg per cubic metre.