Scots bases were prime targets for sabotage Spetznaz forces set to strike at Clyde

Intelligence sources suspect that a network of ''sleepers'' - agents in deep cover, living normal lives in local communities - was in place and that caches of weapons and explosives had been buried at key points.

These were smuggled in by trawlers, transferred in boxes of fish at sea, or dropped off by long-distance lorry drivers at designated spots. They were then squirreled away, sealed in waterproof containers, and buried within striking distance of the targets for which they were intended.

But the main effort in the hours preceding the outbreak of hostilities would have been mounted by teams of Soviet Spetznaz commandos, the Kremlin's equivalent of the SAS. The Soviet high command had 30,000 of these highly-trained soldiers available.

Assaults on defended locations such as Faslane were judged too important to be left to a handful of agents whose last experience of demolition and weapons handling might have been a decade or more earlier.

Brigadier Rory Walker, the retired security chief for the Army north of the Border, was convinced that Spetznaz operatives had carried out detailed reconnaissance of their targets in the guise of long-distance drivers.

He said: ''France, Greece, and Italy all had large and active communist parties at the time. The truckers' unions were heavily infiltrated. It was easy enough to substitute Spetznaz agents for regular drivers on container runs all across Europe.

''Given the remote nature of much of Scotland and its need for resupply of Highland and other communities by road, there was ample opportunity to choose routes via both east and west coasts.

''This gave them the chance to arrange for overnight stops so they could eyeball Faslane, Holy Loch, the wartime command bunker at Pitreavie, the naval dockyard at Rosyth, and several secret communications centres. All would have been key targets for pre-emptive strikes.''

The Royal Navy moved strong detachments of Commacchio Company, the Royal Marines' nuclear security force, into Faslane and Rosyth, to provide ground defence against the expected attacks. For public consumption, they were there to counter incursions by the growing ''peace camp'' protesters located just beyond Faslane's main gate.

The RAF Regiment took delivery of Scimitar and Scorpion armoured vehicles to give them mobility and firepower at the Leuchars, Lossiemouth, and Kinloss airbases. The first two were crucial fighter defence components against incoming Russian bombers.

Kinloss was the home of the Nimrod maritime surveillance squadron tasked with locating Soviet nuclear submarines as they crossed into the Atlantic sea lanes to attack troop convoys from America. Its neutralisation was a top Soviet priority.

Edzell in Angus was a top secret US Navy communications centre able to pass orders to submerged allied submarines by means of ultra-low-frequency signals. It shared a priority for destruction with Kinloss.

The US Navy Seals - American equivalents of Britain's Special Boat Squadron - and US Marines provided unobtrusive security at ''RAF'' Machrihanish, the longest airfield in Europe and a vital element in the planned ''air bridge'' reinforcement of both the UK and the US Army in Germany.

Machrihanish was also the forward base for Seal teams whose job was sabotage and demolition behind Soviet lines. And it provided covert sanctuary for U2 spy planes and, later, for the SR71 Blackbird missions.

Most of the bases were in areas where approach and concealment was easy. All would have been attacked by a combination of Spetznaz assault groups landed from submarines and others infiltrated into the country in the weeks leading up to war.

As a pre-emptive measure, there were secret plans - still classified three decades on - to ''detain'' up to 30,000 known and suspected communist activists and others in Scotland in internment camps whenever general war was judged to be inevitable.