How much alcohol can I drink and still be safe to drive?

Alcohol slows drivers' reactions and impairs judgement, vision and driving ability. If you drive with a blood alcohol level at the legal limit you are three times more likely to be involved in a crash than if you hadn't had a drink. 

The legal blood alcohol limit is 80mg per 100ml of blood for adults aged 20 or over. There is no rule about how many drinks it takes to reach the limit. It depends on personal factors, for example height, weight, what you've had to eat and tiredness. 

If you are under 20 you shouldn't drink any alcohol before you drive. Your limit is 30 milligrams for every 100mls.