Being in charge of a vehicle with excess alcohol - the limit

The current limit is 35 micrograms of alcohol per litre of breath or 80 millilitres of alcohol per 100 millilitres of blood. However, if the lowest reading is 39 micrograms or below, you should be released with a warning.

Between 40 and 50 micrograms you must then be given the option of blood/urine tests. It is for the police to decide which of these options to use. A urine sample is on the basis of 2 samples within 1 hour. A blood sample must be taken by a police surgeon. You can demand 2 blood samples are taken which can be useful in defending the charge. If you are not given this option you may escape further prosecution.