There is a faint smell of floorpolish in the rooms given over to the Kurt Schwitters Exhibition at the Tate, and an equally faint but all-pervasive recording of Schwitters reciting his own poetry. It comes from a bakelite radio set in a corner of the central room, an unending sequence of incantations, rhythmically repeated vowel sounds and gabbled fragments of words, sometimes rising to a climax, sometimes just droning on, but never stopping for more than a second or two of scratchy silence. On the weekday morning I was there the rooms were virtually deserted, and the gallery attendants seemed oppressed and irritated by it: a humourless, grey, nasal voice, a lunatic gabbling to himself in a padded cell, long ago and far away, but still conveying pain in 1985.

On Schwitters’ gravestone in Ambleside in the Lake District, before his remains were returned to his native city of Hanover, it said simply Kurt Schwitters/1887–1948/ lnventor of Merz. ‘Merz’ came into existence in the aftermath of the First World War, when he tore up the words Kommerz- und Privatbank, and