Thatcher approved shoot-to-kill policy at Faslane naval base

HMS Vanguard docked at Faslane in 2006. Newly released papers reveal Margaret Thatcher ordered security at the base to be stepped up following a break-in by protestors. Picture: Jeff Mitchell/Getty Images

Margaret Thatcher approved a shoot-to-kill policy at the Faslane naval base after a break-in by anti-nuclear protesters left the prime minister “utterly horrified”.

Secret Cabinet Office papers released by the National Archives in London shed new light on one of the worst security breaches in the history of the UK’s nuclear deterrent.

Three men managed to break into the control room of a missile submarine armed with nuclear warheads, prompting condemnation of “a most astonishing record of negligence” from Mrs Thatcher.

Her senior advisers warned of “incalculable” consequences had the break-in been carried out by terrorists and not protesters. It can be now be revealed that military personnel and police were disciplined in secret over the incident on 10 October 1988 in order to deny the anti-nuclear movement a publicity coup and stop terrorists learning of weaknesses in base security.

The breach came against the ­backdrop of years of protests against the presence of US nuclear weapons at Greenham Common in Berkshire, and continued nuclear tensions despite the imminent end of the Cold War.

The prime minister was informed within hours of the breach, with a handwritten note from her foreign affairs adviser Charles Powell stating: “This is a very serious matter indeed. Had they been armed terrorists, the consequences would have been incalculable. After all the assurances which you have received about the security of our nuclear weapons, this is a bad lapse. I think you should make your concern known.”

In her own handwritten response, the prime minister said: “I am utterly horrified. Examples of slackness in sensitive matters keep coming to light. I must have an urgent report. We could all have been put in grave danger.”

Passing on Mrs Thatcher’s demand for a full report to the Ministry of Defence, Mr Powell said the prime minister was “absolutely appalled” by the breach in security.

When interim findings were reported to Number 10 on 21 October, Mr Powell wrote: “It gets worse, if anything.” The prime minister’s note reads: “A most astonishing record of negligence”.

The interim report describes how, just after 1:30am, four men cut through the perimeter fence at a spot where barbed wire coils had been removed by repair crews.

The perimeter alarm failed to go off because it had been mysteriously “inhibited” by someone in the police control room, with investigators noting: “We need precise answers before decisions can be made on the question of culpability.”

Three protesters made their way through the base without being seen because the dock was cluttered with contractors’ cabins and engineering equipment, floodlights were not working, and guards in two positions had been given a tea break.

Intruders made their way towards HMS Repulse, a Polaris-class submarine carrying nuclear missiles. They dashed down a gangway through a broken gate and into the vessel via a hatch which should have been locked.

A Royal Marine sentry spotted them boarding the submarine and raised the alarm just after 2am, but “did not open fire because he did not consider the intruders to be hostile within the definition of his rules of engagement,” the interim report notes.

A fifth protester was only noticed by guards when a member of the public approached one of the gates to the base with some clothes for her. Police then discovered a woman had swum across Gare Loch and climbed on to one of the floating docks, where she had sat for an hour without being seen.

A Board of Inquiry made 42 recommendations to tackle “a sorry succession of security lapses”, leading to guards being given the power to shoot intruders.

The Ministry of Defence’s final report to the prime minister states: “The rules of engagement governing the armed guards on the Polaris jetties have been amended, with the agreement of the law officers, to make it clear that they may, as a last resort, open fire to prevent a perceived threat of sabotage not only to nuclear warheads but to the submarine.”

Declassified papers reveal administrative action was taken by the commander-in-chief of the Naval Home Command against six naval officers, including the commodore of the Clyde base, and four ratings. A chief superintendent, a superintendent and a chief inspector were similarly disciplined by the Chief Constable of the MoD police.

Further action was taken by commander-in-chief of the Fleet against sailors on HMS Repulse, and by the Commandant-General of the Royal Marines against Faslane guards.

the prime minister was advised that punishments would be “no less severe than those likely to result from court martial”.

However, no public hearings were held because the MoD feared “such exposure would not only provide opportunities for the anti-nuclear movement, but could also be damaging to security by, for example, alerting terrorist groups to potential weaknesses in the base’s security”.

The case against the three men who boarded HMS Repulse collapsed when they appeared at Dumbarton Sheriff Court in 1989. Despite efforts to tighten security, a similar breach took place just eight years later, when Faslane Peace Camp protesters Claire Davies and Mhairi Logan swam across Gare Loch in 1996 and climbed on to HMS Sceptre, a nuclear-powered hunter-killer submarine that did not carry ballistic missiles.

They climbed through an open hatch into the submarine’s laundry and stores area, making a call on a BT cardphone installed there for crew before being apprehended and handed over to MoD police.

Ms Davies and Ms Logan were released the next day by the procurator fiscal, ten minutes before their trial on charges including breach of the peace was due to begin.