Employers' increasing efforts to stamp out drink-driving after Christmas parties has been illustrated by a seasonal surge in self-test breathalyser sales, said a Norfolk manufacturer.

Dr Mike Garside, a director of Access Diagnostic Tests based in Aylsham, said his business sees sales soar in the three months leading up to Christmas.

Companies buying quick and easy tests to put in adult 'party bags' for their workers to take home after festive get-togethers leads to an upsurge so large it accounts for half of the sales of the products every year, he said – and that amount is growing.

Dr Garside said: 'Companies are proactive in buying the tests, which can give you an indication in a matter of minutes as to your blood alcohol level. Sometimes it's to give to employees, sometimes it's to push more generally for a healthier workforce.

'The industries which are most proactive in testing tends to be the construction industry, however increasingly we're seeing demand from the logistics industry who don't want their drivers in haulage or similar getting behind the wheel of company cars the day after a Christmas party.'

A former GP, Dr Garside continued: 'The problem is becoming a more complex issue because of street drugs, and the fact that even over-the counter prescriptions for pain medication can sometimes act in the same way as an opiate.'

The company, which has a £2.2m turnover, ships up to 15,000 single breathalysers and around 5,000 saliva alcohol tests in the three months before Christmas, plus 5-7,000 combined drug and alcohol saliva tests.

The emergency services joined the business community in warning employees to drink responsibly this Christmas.

Last year more than 150 people were found over the limit in a drink and drug driving campaign launched by the Norfolk and Suffolk Constabularies.

Statistically young men form a large proportion of those who are stopped for drink driving, with that number increasing. Women over the age of 35 are also an increasingly large proportion of drink drivers.

Insp Jon Chapman from the Joint Roads and Armed Policing Team, said: 'Many of these people have professional careers, they may have children and grandchildren and yet they are still choosing to get behind the wheel after consuming alcohol. We want to continue to drive home the message and make drink-driving socially unacceptable.'