Road Transport Act 2013

For the purposes of this Act, the concentration of alcohol present in a person’s breath or blood may be expressed as follows—

in the case of a sample of breath that is measured by a breath analysing instrument or other breath testing device that provides a reading or result by reference to alcohol present in the breath—the amount of alcohol in grams in 210 litres of breath,

in the case of a sample of breath that is measured by a breath analysing instrument or other breath testing device that provides a reading or result by reference to alcohol present in the blood—the amount of alcohol in grams in 100 millilitres of blood,

in the case of a sample of blood—the amount of alcohol in grams in 100 millilitres of blood.

An amount of alcohol in grams present in breath when measured by reference to 210 litres of breath is equivalent to the same amount of alcohol in grams present in blood when measured by reference to 100 millilitres of blood.

Accordingly, any offence against this Act relating to the presence of a specified concentration of alcohol in a person’s breath or blood at the time of the occurrence of a particular event is a single offence regardless of whether the concentration of alcohol concerned is measured by reference to the amount of alcohol present in breath or in blood (or both).