The turnout was 72.2 per cent – higher than average for recent polls, but lower than the 85.6 per cent turnout for Scotland's referendum on its membership of the United Kingdom in 2014.
Specifically, 33,568,184 Britons voted in the referendum, which is almost certain to result in an unexpected vote to Leave the EU.
The population of the UK is just over 65m, according to separate figures published by the Office for National Statistics this week.
The result of the referendum has shocked onlookers. Polls had signalled a victory for Remain, right up until Thursday night. A YouGov poll published at 10pm predicted 52 per cent of votes going to Remain, and 48 per cent to Leave.
The pound climbed to $1.50 amid optimism over the result, but dropped sharply as results came through. Sterling was down below $1.34, with 29m votes counted.