This was the reason for Slovo's fury against Norma Kitson's public protest in Trafalgar Square. Norma was a well-known member of the ANC and Communist Party and thus posed a significant  threat to the deal with MI5. She was immediately expelled from both organisations but she remained a threat and an embarrassment, for many ordinary members of the AAM knew and sympathised with her and could not understand why her egregious militancy was being punished. Slovo could hardly explain, Marxist revolutionary though he was, that he had a secret agreement with the British police and secret service. When David Kitson arrived in London Slovo must have feared the worst should David lend his huge prestige and popularity to the protest: hence his demand for David to denounce Norma and the need ever after to send David and Norma to Coventry. This extremely cruel tactic was taken up by the SACP so that the ban against the Kitsons continued to operate even after Slovo's death. Mandela professed himself puzzled by it and said the Kitsons were heroes, but even this counted for nothing.

Now, at last, David Kitson is beyond such spitefulness (Norma died in 2002). I knew the Kitsons well and often stayed in their house in Harare, weirdly decked out with the mementoes of decades of anti-apartheid struggle in London. But what is far weirder is the part that the Kitsons played in British history. The Comet's fail-safe undercarriage that David designed always worked, and Norma, unwittingly and single-handedly, almost torpedoed the most remarkable arrangement that the British government has ever reached with a foreign revolutionary movement. Sir Paul should count himself lucky that anti-apartheid didn't happen on his beat and should perhaps mull the advantages of a discreet deal with the NUS.