How to use the online alarm clock
Ten at night is when the polls close. On a British general election day, voting ends at ten o'clock precisely and the exit poll is published at that moment, which is why so much of the country is watching the clock rather than the television in the minute beforehand. Anyone who has not voted by ten does not vote.
On ordinary nights News at Ten has held the slot for most of its history, and last orders are being called in a good many pubs. For people on nights it works the other way round: ten o'clock is the alarm to get up, get dressed and be on shift before eleven.
It is also the hour a lot of people set a hard stop for revision or work, on the grounds that anything done after it will need redoing in the morning. Every minute from 10:00 pm to 10:59 pm has its own page beneath this one.