Question to the Department for Transport:

To ask Her Majesty's Government for what reason the drink drive limit in England and Wales was set at 80 milligrammes per 100 millilitres of blood; and what scientific studies, if any, were the basis for determining that limit.

The Road Safety Act 1967 made it an offence to drive a vehicle with a blood alcohol concentration (BAC) in excess of 80 milligrammes of alcohol per 100 millilitres of blood and obliged drivers to submit to a screening, breathalyser test at the roadside in certain circumstances.

In 1966 Professor Allsop published a paper “Alcohol and Road Accidents” which stated that earlier research by Professor Borkenstein in 1964 showed that with “blood alcohol levels above 80 mg/100 ml, the risk of being involved in an accident is higher”.

Professor Allsop’s report provided the basis for setting the drink drive limit in 1967.