Your report (Suspect in Yvonne Fletcher murder freed after national security worries, 17 May) raises a serious unanswered question: what were the “reasons of national security” that meant “key material” was not made available to the police for use in court “in evidential form”?

The answer could lie in a number of unchallenged reports that, a day before Fletcher was shot, GCHQ intercepted a prior warning of a possible attack on demonstrators outside the Libyan People’s Bureau in London. A message from the Bureau to Tripoli included the option: “To fire on them from within the Bureau”. This is reported in Spies, Lies and Whistleblowers, by the former MI5 officer Annie Machon; in GCHQ, The Uncensored Story of Britain’s Most Secret Intelligence Agency, by Richard Aldrich; and in Christopher Andrew’s official history of MI5, The Defence of the Realm. GCHQ’s intelligence was not passed on to the Metropolitan police or MI5 until after the shooting.

Richard Norton-Taylor

London

• The UK government’s case has always been that the Libyans shot dead PC Yvonne Fletcher out of pure wickedness – implausible prima facie because it would make the closure of the Libyan People’s Bureau inevitable. In fact the UK government was warned by the Libyans several times on 16 and 17 April 1984 – both in Tripoli and London – that they expected trouble involving firearms. Western intelligence knew well that the violent Libyan dissident faction it supported – Al-Burkan – had agents inside the embassy. Outside the building, Saleh Ibrahim Mabrouk uttered the last warning to police on the morning of the shooting and was promptly arrested; he was in custody when the shots were fired.

Despite the deafening warnings, the UK government took no preventive action – not even surveillance cameras were positioned – and several individuals escaped from the rear of the LPB before the lockdown began. No wonder they still want to keep it all secret under the “national security” blanket.

Dr Kevin Bannon

London

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