04. The drink-driving law

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  • In December 2014, the drink-driving limit in Scotland was reduced to 22µg/100ml of breath. You may also have seen it in the media expressed in its blood alcohol limit of 50mg/100ml (0.05%BAC). This is the same limit for Ireland. Ireland also have a lower limit again for professional, learner and novice drivers of 9µg/100ml. In the rest of the UK (England, Wales and Northern Ireland) the limit is 35µg/100ml breath for all drivers.
  • Today the initial road side breath test is followed up by two additional breath tests back at the station using an evidential breathalyzer. The lowest of the two readings is used to decide whether the driver is within the legal limit or not.
  • It used to be that if the lowest reading is below 50µg/100ml breath (in England, Wales and N.Ireland) then a blood test could be requested.  This is no longer the case and only the breath test result is used, as the time required to secure a blood sample could give the suspect time to metabolise the alcohol and pass the blood test, subsequently getting away with drink-driving.


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