The Government has promised not to ban smoking in company cars when its new Health Bill comes into force in 2007.

But vehicles used by more than one worker or as a ‘place of work’, such as a delivery van, will come under the law banning smoking from public places.

Speaking at a House of Lords committee discussion on the Health Bill, Lord Warner, Labour peer and Minister of State for the Department of Health, said: ‘We do not intend to prohibit smoking in all company cars. Where that car is used by only that person for work purposes, it would not be required to be smoke-free. Vehicles used as a place of work or business vehicles, such as delivery vans and post vans, will be smoke-free unless the vehicle is only ever used by and owned by one person.

‘However, if the lorry were shared – for example, used in the morning by one person who smoked and in the afternoon by another person –smoking would not be permitted at any time, as the second person would be exposed to the risks from second-hand smoke.’

Critics of the Bill have suggested such regulations are confusing and unenforceable, pointing to an attempt to ban smoking from company vehicles in California which failed because of a lack of clarity over which vehicles came under the law.

Cross bench peer Lord Monson said: ‘When the police see a car going by with someone in the front they believe to be smoking, that person might actually be holding a Biro, but at high speed the police may mistake it for a cigarette.

‘Will there be high-speed car chases with people being forced on to the hard shoulder to be asked if they can provide proof that theirs is a private car, not a company car? The idea is ridiculous.’ The Scottish parliament banned smoking in ‘public’ vehicles such as taxis and vans in March, although company cars are exempt.