Now the top secret Soviet maps of Scotland which the Red Army drew up with the goal of occupying the country can be revealed. The charts prove beyond any doubt that agents of the Kremlin created detailed charts of huge swathes of the nation.

The maps show Scotland's major cities, Glasgow, Edinburgh, Aberdeen and Dundee, but also less obvious strategic targets such as Kilmarnock and Dunfermline.

And the maps also feature a host of details that would never be shown in any Ordinance Survey map, including military facilities, the width of key roads and even whether groups of buildings are fireproofed.

The extraordinary Cold War documents have been gathered by map expert John Davies. The cartography collector discovered the classified military maps during a visit to Latvia.

He said: "You have got to speculate as to how maps of these complexity were put together. A lot of it could have been done through aerial surveillance, either by satellite or high-altitude reconnaissance planes. But the maps also include detail which just could not have been observed from the air. That means that they almost certainly had people on the ground in the UK compiling these maps."