Reference · Legal limits
UK drink-driving limits by specimen and nation
Scotland’s prescribed drink-driving breath limit is 22 micrograms of alcohol per 100 millilitres. The limit is 35 in England, Wales and Northern Ireland. Scotland also has lower prescribed limits for blood and urine, each expressed in milligrams per 100 millilitres.
Sources checked
- 01Breath
22 in Scotland and 35 in England, Wales and Northern Ireland, in micrograms per 100 millilitres. Source 1
- 02Blood
50 in Scotland and 80 in England, Wales and Northern Ireland, in milligrams per 100 millilitres. Source 1
- 03Urine
67 in Scotland and 107 in England, Wales and Northern Ireland, in milligrams per 100 millilitres. Source 1
Compare the two jurisdiction values within the same card. Breath uses micrograms. Blood and urine use milligrams.
The lower Scottish limits apply to the same specimen types
The GOV.UK table gives two jurisdiction groups for each specimen. For example, the breath comparison is 22 against 35 in the same micrograms-per-100-millilitres unit. A driver crossing between Scotland and England crosses between different prescribed limits. Source 1
Read the specimen and unit with the number
Breath is reported in micrograms per 100 millilitres. Blood and urine are reported in milligrams per 100 millilitres, but each is a distinct specimen with its own threshold. Read a number against the row for the specimen that was actually measured. Source 1
A limit cannot predict a person’s reading after drinking
GOV.UK says the relationship between a number of drinks and a reading differs by person. Body size, metabolism, what was eaten and other factors can affect the result. The official figures are legal specimen thresholds. Source 1
The Highway Code advises avoiding alcohol before driving
The Highway Code explains that alcohol can reduce coordination and slow reactions even below the legal limit. It advises against drinking at all before driving and notes that alcohol can still affect a person the following morning. Source 2