There’s not much left to see of the Berlin Wall at Checkpoint Charlie. The setting for countless cold war spy films, crossing point from Communist east Berlin into the American sector in the west, is marked by a pile of sandbags and the decrepit wooden hut where the US soldiers sat. An exhibition of grainy photographs has been posted on the hoardings of a building site on the Friedrichstrasse. A block down the street, a chunk of graffiti-sprayed concrete has been stuck beside the door of a very modest museum. That was the wall.

Berlin is a city of living history, but it does not do nostalgia. The wall that once served as the most powerful symbol of the cold war confrontation has been reduced to a few select memorials. The rest has been commoditised, chunks of concrete communism distributed for capitalist gain. Helmut Kohl, former chancellor, has one in his garden.

Fifty years ago tomorrow, Berliners woke up to find a barrier through their city. Both western allies and they seem to have been taken by surprise. It was a desperate measure by Walter Ulbricht, the East German Communist party leader, to stop a drain of refugees from his country. Some 3m, mostly skilled workers, had already fled to the west. In July it reached 1,000 a day.