December is traditionally the busiest month for the officers policing Cambridgeshire's roads, with more people caught driving under the influence of alcohol or drugs than at any other time of year.

A clampdown on drink-driving last year was hailed a success after the number of people arrested was cut by a quarter, and road safety officers are hoping this year's figure will be even lower.

And from today, police will be carrying out random stop checks on roads throughout the county, using specially-designed "field impairment tests" to check whether drivers have been using drugs.

They will also be patrolling the highways in the mornings, as well as the evenings, in a bid catch out drivers still under the influence from the night before.

Casualty reduction officer Pc Tony Barrios said anyone driving under the influence this Christmas could expect to be caught and feel the full force of the law.

He said: "Over the next few weeks drivers should expect to see a highly visible police presence on the county's roads as we target those who drive under the influence.

"Drink and drug-driving enforcement is a vital tool in the reduction of fatal and injury collisions.

"Our message is clear - if you drive under the influence of drink and drugs, expect to be caught and brought to justice.

"The maximum penalty for drink-driving is a six-month prison sentence, a £5,000 fine and a driving ban of at least 12 months. Is it really worth the risks?"

Last December, police in Cambridgeshire caught 149 people behind the wheel while under the influence of drink and drugs - 25 per cent fewer than the 201 caught in 2006, but still an average of five drivers each day.

Despite the significant drop, Pc Barrios said the number of people still ignoring the law and common sense was still too high.

He said: "It was good to see last year's figures reduce but it is always disappointing to catch people driving under the influence.

"Cambridgeshire Constabulary is committed to reducing the number of drink-drivers and we will do all we can to ensure that those over the limit or under the influence of drugs are caught and dealt with appropriately.

"Drink and drug drivers are not only putting their own lives at risk but also the lives of others."

The campaign is being backed by Peterborough City Council, which is part of the Cambridgeshire Road Safety Partnership.

Councillor Wayne Fitzgerald, cabinet member for the environment and transport, said: "This campaign is sending a clear message to motorists not to drink and drive this Christmas.

"People must remember their responsibilities as drivers, which are not just to consider themselves and their families but to think of the safety of others whenever they take to the road."