Ten in the evening is when the day is formally wrapped up. The main late news bulletin goes out, the general election exit poll is published at exactly this time on polling day, and a large part of the country begins thinking about bed.
Transport starts thinning: last direct trains from the major cities leave between roughly ten and midnight, and anyone relying on a connection needs to have checked the timetable long before. Overnight motorway roadworks begin around now, and the closures that come with them run through until early morning.
For shift workers, 10 pm is a standard night-shift start rather than a wind-down, and for hospital wards it is the point at which the night routine takes over from the evening one. Whichever side of that divide you are on, this countdown gives the precise wait to the next ten o'clock in the evening, resetting the moment it passes.
Common questions
Why is 10 pm notable on election day?
Polls close at ten and the exit poll is published at that exact moment, which is why the hour is watched so closely.