Drink-driving before the limit
Before 1967, British law did not define drunkenness behind the wheel by a number. An offence of driving while unfit through drink or drugs had existed since the 1930s, but proving it depended largely on the judgement of a police officer or a doctor who examined the driver. That meant arguments about whether someone was “unfit” rather than whether they had passed a measured threshold, and convictions could be uncertain. Drivers who had drunk a fair amount but appeared steady were hard to prosecute.
By the 1960s, road deaths were a source of serious public concern. Car ownership had risen quickly, roads and vehicles had not kept pace, and the death toll in Britain ran at several thousand a year. Alcohol was known to be a factor in many accidents, though how large a factor was less well measured than it is today.
The Road Safety Act 1967
The Labour government’s Minister of Transport, Barbara Castle, took up the issue and introduced legislation that became the Road Safety Act 1967. Its drink-driving provisions created a new offence of driving, or attempting to drive, with a blood alcohol concentration above a prescribed limit. The limit was set at 80 milligrams of alcohol per 100 millilitres of blood. It applied in England, Wales and Scotland.
The provisions took effect in October 1967. The Act did not allow police to stop drivers at random to test them. Instead, a constable could require a breath test if he had reasonable cause to suspect that the driver had alcohol in the body, if the driver had committed a moving traffic offence, or if there had been an accident. The test was done at the roadside with a device that gave a first indication. The original equipment used glass tubes containing crystals that changed colour, and the driver blew into a bag. If the result was positive, or if the driver refused, the person could be arrested and taken to a police station for a more exact measurement, using blood or urine samples. Refusing to cooperate was itself an offence.
The offence carried penalties that included a fine, a possible prison sentence and, importantly, a mandatory disqualification from driving, usually for at least a year. The disqualification was the part that most drivers feared, since many depended on their licence for work. Because it was a strict numerical standard, it mattered less whether a driver felt capable or appeared drunk.
Public reaction
The change was controversial. Some publicans and brewers worried about lost trade, and some motorists complained that the law was heavy-handed. Others, including road safety groups and many doctors, welcomed it. The government accompanied the introduction with publicity, and the new device itself, which was nicknamed the breathalyser after the brand name of an early American instrument, quickly became a familiar word.
There was an early adjustment period in which people tried to work out how much they could drink. Because individual blood alcohol depends on body size, food, time and other factors, there was no simple rule, and advice at the time warned against treating a figure such as two pints as a guaranteed safe amount. Modern guidance makes the same point: the only reliable way to stay under any limit is to avoid drinking before driving.
What happened to accidents
Reports at the time indicated a clear drop in road casualties in the months after the law took effect, and the effect was particularly noted around late-night weekend hours, when drink-related crashes were most common. Over the following years, however, the improvement was reported to have faded partly as drivers realised the chance of being tested was modest. Later research and commentary have treated the Act as an important step in changing attitudes, but the size and permanence of the early effect are debated, and other measures, including vehicle improvements and seat belts, also contributed to the longer-term fall in deaths. The overall number of road deaths in Britain has fallen greatly since the 1960s, which cannot be credited to any single law.
Gradually, public attitudes also shifted. Drink-driving moved from something often treated as a minor lapse to something widely seen as irresponsible, a cultural change that took decades and that campaigns, enforcement and tougher penalties all supported.
Later changes
The 80 mg figure remained the limit in England and Wales, though Scotland lowered its own limit in 2014. Breath testing equipment moved on from crystal tubes to electronic instruments, and police powers were later widened in ways that reduced the need for a specific suspicion. In the years that followed, penalties and enforcement were strengthened, and the offence has been revised in various ways.
Where it fits in 1967
The breathalyser is one of several laws from 1967 that touched ordinary people directly. Alongside the Abortion Act and the Sexual Offences Act, it shows a legislature willing to act on social questions in a single year of change, though the motivation was different: road safety rather than personal morality, and the evidence for it was easier to measure. For many people, a breath test at the roadside was the way the legacy of 1967 first touched their lives, and the law still shapes how Britain thinks about drinking and driving.