IN NARNIA, WHEN the bad White Witch ruled, it was always winter but never Christmas. The oddity of our own time is that so much of winter – pretty well the whole of December and the tail end of November – is taken up by a premature Christmas. By Christmas Eve, the festive spirit will have been at large for about a month, rather than being bottled up until then. Hilaire Belloc used to go into his garden to cut down the Christmas tree at 5.30 p.m. on Christmas Eve … well, I’ve picked up a tree discarded on the street way before that.

For partygoing Londoners, the Christmas season goes through stages: the parties start in early December, peak in the second week, and peter out about seven to 10 days before Christmas, when people begin to drift away.