How to use the online alarm clock
Five in the morning is when the broadcast day restarts. Radio 4 comes back from the World Service with the shipping forecast, and Farming Today follows at a quarter to six, which for a great many rural households is the actual signal to get moving. The first trains are pulling out of depots, and the first Underground services are only half an hour away.
It is a heavily used hour for people whose commute is long rather than early. An hour on a train into a city centre, plus the walk at either end, turns a nine o'clock start into a five o'clock alarm, and the calculation is unforgiving enough that the exact minute matters.
Construction sites, distribution depots and hotel kitchens all change over around now, and runners who want the roads to themselves before the traffic builds tend to pick this hour too. The minute pages here work the same as the rest of the site: open one, leave it open, and it will sound when the time comes.