There are strict limits as to the amount of alcohol that you may have in your blood when driving. The amount that you can drink before being "over the limit" will vary from person to person. Most people can have a pint of beer or a glass of wine before going over the limit, for some people it will be more than this. However the only sure way is to not drink and drive at all. Even a small amount of alcohol can affect your concentration and reaction times. It is a myth that a small amount of alcohol makes you a better driver - the reality is you may feel more confident, but this is an illusion - in reality your driving cannot be better.
There are devices on the market to test your breath alcohol. Remember, these only give you a snapshot at the time of taking the test and may not be very reliable. Make sure you follow the instructions. Novelty "key ring" style testers are unreliable and should be avoided.
The limits are:
80 milligrams of alcohol per 100 millilitres in blood
35 micrograms of alcohol per 100 millilitres in breath
107 milligrams of alcohol per 100 millilitres in urine
Which Breathalyzer is a Best Buy?
If you are stopped and breathalyzed and the result is positive you will be taken to the police station and will need to give a urine sample. The maximum penalty for drink driving is 6 months prison sentence and £5000 fine. If you wish to plead innocent or challenge a drink driving conviction, you are strongly advised to consult a lawyer.