Русско-англо-русский юридический словарь

As from the date on which this Act comes into force a person shall attain majority on attaining the age of eighteen instead of on attaining the age of twenty-one; and a person shall attain majority on that date if he has then already attained the age of eighteen but not the age of twenty-one. (Age of Majority (Scotland) Act 1969)

In English law a person is deemed to attain his majority on the day before his twenty-first birthday, but in Scottish law he attains his majority on his twenty-first birthday. (parliament.uk)