One alcoholic drink could be enough to make it unsafe for someone to drive, scientists have warned.
Although there is no standard amount of alcohol someone can drink to stay within the legal limit, some may think they can get away with one glass of wine or a pint.
But a study suggests just one tipple is enough to 'significantly compromise' a person's feeling of control by altering their brain function.
Scientists said even one is too many and the law should be reformed to mean people driving with any alcohol in their blood should be punished.
One alcoholic drink could be enough to cause unsafe driving, scientists at the University of Sussex have warned (stock image)
Researchers at the University of Sussex did their study by comparing a person's sense of agency before and after they'd had a drink.
The sense of agency is the feeling of being in control of our actions and understanding what the consequences are and when they will happen.
Measuring this was difficult, said the lead author Dr Silvana De Pirro, especially in studies when people are aware of what is being tested.
Researchers relied on another measure called 'intentional binding', which refers how someone sees the relationship between a physical action and its effects.
When people drink their perception of the time between a stimulus, reaction and effect is changed, the scientists said, affecting their decisions and reaction times.
A total of 59 participants drank a cocktail that had doses of alcohol adapted to their body weight to make sure they were within the legal driving limits in England and Wales.
England and Wales has among the most lenient drink driving laws in Europe.
Motorists are allowed to have 80 milligrammes of alcohol per 100 millilitres of blood, 35 microgrammes per 100 millilitres of breath or 107 milligrammes per 100 millilitres of urine.
This does not translate into a fixed number of drinks as people of different ages, weights and alcohol tolerance process drink at different rates.
However, as a rule of thumb most drivers drinking would limit themselves to around one pint or one glass of wine.
But ministers have faced calls