In the UK it’s illegal to operate a vehicle while intoxicated by alcohol, defined, in England, Wales, and Northern Ireland, as having 80 milligrams of alcohol per 100 millilitres of blood or 35 micrograms of alcohol per 100 millilitres of breath. But how long has this been the law?
These limits were introduced by the landmark Road Safety Act 1967 and have reduced the number of deaths caused by drink driving annually from 1,640 to 200.
However, the history of legal restrictions on driving and alcohol predates this law and, in fact, predates the introduction of motor vehicles in the UK in the 1890s.
Here’s a brief history of the laws we’ve put in place to stop people from operating cars - and carriages and steam engines - while intoxicated:
1872: The Licensing Act made it illegal to be drunk in a public place while in charge of a horse, cattle, a steam engine, or carriage. The penalty was set as a fine not exceeding 40 shillings (around £158 in today’s money) or imprisonment, with or without hard labour, for up to a month.
This 1872 law is still the source of some convictions of people intoxicated while operating mobility scooters, with the mobile scooter classified as a “carriage.”
1925: The Criminal Justice Act of 1925 outlaws being “drunk while in charge while on a highway or other public place of any mechanically propelled vehicle.”
1930: There are now around one million cars on the UK's roads and road accident rates are high. Around 7,300 people are killed in traffic accidents in 1930, many times the 1,750 people killed in 2019, when there were 38.7 million motor vehicles registered.
There’s also significant confusion about the definition of “drunk,” as used in the 1872 and 1925 laws. The Road Traffic Law 1930 addresses some of this confusion by stating a driver can’t be “under the influence of drink or drug to such an extent as to be incapable of having proper control of [a] vehicle.”
Three years before, the British Medical Association validated clinical tests for determining if a driver is impaired by alcohol. These include a GP or police surgeon observing a driver pick a coin up off the floor, narrate events earlier in the day, and read a simple passage without slurring.
1931: The first practical roadside breath-testing device is invented in the US. It’s dubbed the “drunkometer.”
1937: Research over the preceding decades has shown that even people who don’t visibly appear intoxicated can be impaired, with delayed reaction times and distorted vision. Although this evidence is presented to a parliamentary select committee investigating road traffic accidents, the committee declines to recommend that drivers be compelled to submit to blood or urine tests. Some campaigners have instead pushed for motorists to be educated and asked to practice self-restraint if they’re getting behind the wheel.
1936-41: Norway and Sweden pass the world’s first drink-driving laws, outlawing driving if the motorist has above a certain blood alcohol concentration and requiring suspected drivers to submit to testing. Denmark and some US states quickly follow but the UK still lacks laws prohibiting drink-driving.
1954: The British Medical Association finds that drink driving causes “several thousand” accidents per year.
1960: The Road Traffic Act makes it illegal to drive, attempt to drive, or be in charge of a motor vehicle on a road or other public place while "unfit to drive through drink or drugs.” But there’s still no legal drink driving limit in the UK.
1962: Another Road Traffic Act, known as the Marples Act, makes it an offence for someone to drive, attempt to drive, or control a vehicle if their “ability to drive properly was for the time being impaired.” While suspects aren’t required to submit to blood and urine testing, those who refuse a voluntary test can have that fact used against them in court.
1964: Research funded by the U.S. government and the beverage industry shows that when a driver’s blood alcohol concentration (BAC) is 80mg of alcohol per 100ml of blood, the risk of an accident rises sharply.
1967: The Road Safety Act 1967 sets the first legal blood alcohol limit in the UK. It becomes illegal to drive, attempt to drive, or be in charge of a motor vehicle with a BAC of 80mg of alcohol per 100ml of blood or the equivalent 107 microgrammes of alcohol per 100ml of urine. Testing is also made compulsory. Suspected drivers who refuse to produce blood or urine samples for laboratory testing can be prosecuted or punished as if they were discovered to be drink driving.
Also in 1967, the breathalyser is approved for use in the UK as a means of testing BAC at the roadside. The Road Safety Act states that anyone who refuses to submit to breathalyser testing is guilty of an offence and can be arrested and fined up to £50 (£643 today).
The Ministry of Transport publicises the new laws through a major publicity campaign, with TV, film, and newspaper advertising.
1968: The first breathalyser, the Alcotest 80, begins to be used by UK police.
Within just a year, the drink-driving limit and the Alcotest 80 help to cut alcohol-related road traffic accidents by 15% to 25%.
1981: The Road Safety Act of 1981 authorises evidential breath testing - testing intended to be introduced as evidence and more accurate than the provisional breath testing done by police on roadsides. The act sets the limit as 35 microgrammes of alcohol in 100 millilitres of breath.
1983: Evidentiary breath testing begins with the Lion Intoximeter 3000. This device is more accurate that the portable hand-held breathalysers used on roadsides.
1991: The Road Traffic Act of 1991 introduces a new offence of ‘Causing death by driving while under the influence of alcohol or drugs,’ with a compulsory prison sentence of up to five years.
Courts are also now able to refer drivers who have been disqualified to drink driving rehabilitation courses.
2000: Drink driving rehabilitation courses are expanded so courts across the country can refer convicted drink drivers to them.
2004: The maximum penalty for causing death by driving under the influence of alcohol or drugs is increased to 14 years in prison.
2014: Scotland reduces the legal drink drive limit from 80 to 50mg of alcohol per 100ml of blood in line with most of the European Union. The limits in the rest of the UK remain the same.