Time — and how we count it: 24-hour clock will have its day

The predisposition of bureaucrats and politicians to fall for ideas that might be labelled fairly as barmy isn’t a uniquely 21st-century affliction. In September 1919, the UK’s Home Office set up a committee to consider introducing in Great Britain and Ireland what the Daily Telegraph said would be a “twenty-four hour method of timekeeping ... a change in the clock dial, with all the twenty-four hours marked upon it”.

Ireland played an accidental part in firing up enthusiasm for the 24-hour clock. While travelling here in 1876, Scottish-Canadian engineer and inventor Sandford Fleming missed a train because a printed timetable incorrectly listed p.m. instead of a.m. He proposed a single 24-hour clock for the entire planet. More usefully, he designed Canada’s first postage stamp and engineered most of the Canadian Pacific Railway.

The 24-hour notation, also known in the US as military time, is the preferred usage in specialist areas aviation, public transport, emergency services, and computing for the avoidance of fatal error and ambiguity. But even in this digital epoch, cutting the day into two 12-hour pieces remains one of the most confirmed of our habits when setting about our more quotidian chores; while the screen might say it’s 15.00, we all know that is what we call 3pm. That enduring “immense unpopularity” of the 24-hour clock for everyday use has saved us from watch and clock faces that would be either indecipherable or ridiculously outsized.