Steve Whitehouse, project manager at the Lancashire Partnership for Road Safety, says just one unit of alcohol – about half a pint of beer –makes people a "liability" behind the wheel.

He is calling for a major debate on the legal limit in a bid to bring the UK into line with the rest of Europe.

But he stopped short of saying the country should adopt a zero-tolerance approach.

He said: "After one unit of alcohol, people's risk actually doubles.
Even after one unit of alcohol people become a liability on the road.

"We are not necessarily pushing for zero tolerance because there are issues around that, but we need people to realise you can't just think of these magical figures: You can't think I have had two halves so I'll have another.

"Legally you may be able to but your actual risk increases.

"It is something I think we would have to debate on. Most of Europe has a lower alcohol limit now than the UK and I know we have been working with the Government at national level and regionally to at least try to get a debate going about what that level should be because we want people to be able to enjoy alcohol sensibly."

Mr Whitehouse, who last week said speed cameras were here to stay on Lancashire's roads, says a zero tolerance approach could lead to problems – because if people drink the night before or take some forms of medication, low levels of alcohol could show up on a breath test.

But he added: "I personally would support a move to reduce the drink drive limit. I would not want to come up with a figure at the moment because a lot of research needs to be done on what that figure should be."

In 2005, the latest figures available, 2,723 people were convicted of drink driving in Lancashire.