Oil Safe - Protecting Britains Oil from Terrorist Attack
The threat of terrorist both home grown and international against the North Sea Oil Instillations was brought to the attention of the then Prime Minister Jame Callaghan in 1976.
A confidential briefing from the Ministry of Defence was sent to the Prime Minister which described how the Royal Marines would launch a clandestine mission in the North Sea if an offshore installation was taken over by a terrorists group.
"There are only two ways of getting on to a rig occupied by well-armed terrorists: from sea level up the legs or from above by helicopter. The most favoured tactic would be to introduce the SBS (Special Boat Squadron) on to the rig by clandestine means; there are several ways of doing this: by submarine from which they would make an underwater exit, by rigid raiding craft from a surface ship or by parachute into the water upstream of the rig."
"They would then swim to the rig and climb the legs, using magnets if necessary. Once they were on board they would attempt to pin the terrorists down, or divert their attention while the main assault force landed on the rig by helicopter - and this may have to be at the hover if the rig's landing platform is obstructed."
The first exercise was planned for July 5 or 6, 1976, with warships, helicopters and Marines all deployed and directed from maritime headquarters at Pitreavie.
Plans included the provision of an "immediate reaction troop" of 22 men from 45 Commando Royal Marines based at Arbroath "at two hours' notice to emplane".
An assault troop of 90 Royal Marines from home-based Commando units were at 24-hours' notice. An explosive bomb disposal team and several Royal Navy Sea King helicopters were also on standby. The briefing was sent to the Prime Minister ahead of a visit he was due to make to one of the offshore oil and gas rigs in the North Sea at the time.
Officials rated the threat level of such an attack as low, but added that although there was no evidence that a terrorist organisation was planning to attack any of the installations, the possibility could not be ruled out.
They said it would be "embarrassing and difficult for the government to deal with determined terrorists with no regard for human life on a highly flammable platform which if damaged could cause considerable economic disruption".
A letter to Mr Callaghan from the Home Secretary headed SECRET', dated July 28, 1976, said that the exercise revealed "a number of deficiencies in our procedures".
The subsequent lines in the letter, which were underlined in blue pen by Callaghan, stated that action was under way to improve the contingency plans.
At the top of the letter a note scrawled by Mr Callaghan shows how concerned he was. It reads: "I would like to be kept in touch with developments and to be assured that our security arrangements are as secure as possible."
These early exercises shaped a method of assault that is still practiced today.