“… A newspaper ad appealing for witnesses even misidentified the victim. The deceased was a member of the Central Committee of the Revolutionary Communist Party of Britain (Marxist-Leninist). Over the preceding years he had clashed numerous times with far-right political groups in East London. Just six weeks before his death he had been arrested at the House of Commons for scattering leaflets and shouting, ‘This house stinks of racism!’ during a speech by the Ulster Unionist MP (and former Conservative Health Minister) Enoch Powell. In the coded communications of his Party, the dead man had been known as Ernest. But he was born Cornelius Cardew, in Winchcombe, Gloucestershire, in 1936, and he was one of the most fascinating composers of the 20th century. Michael Nyman had first spoken of musical ‘minimalism’ in a review of one of his works; Brian Eno was a fan. So was Robert Wyatt, who called…