London’s most famous door, probably .in fact Britain’s leading door, is that of 10 Downing Street. Because the prime minister lives, extraordinarily, in a terraced house on a street, the front door cannot escape attention. You never see the front door of the White House or the Elysée Palace. Buckingham Palace surely has a front door, but it must be subsumed somewhere in the canopied elaboration of what is called the Grand Entrance. 

When Mary Wilson lived at No 10, she wondered about the front door. It was subject to such heavy use it frequently had to be repainted. Was it not possible to reduce the number of people going through the door each day? The answer was no. It is really the only way into the building. Everyone who works at No 10 must pass through it.

Leaving it open doesn’t seem a possibility either. It opens and closes constantly, apparently of its own accord, another unique feature. Somehow when the prime minister or some minion is outside in the street wanting to get in, the door obligingly opens. On one occasion, though, it didn’t. In December