Stalin planned to blow up more than 1,200 buildings including the Bolshoi Theatre and St Basil's Cathedral if the Nazis ever took Moscow, documents have revealed.

An exhibition of secret papers staged to commemorate 90 years of military counter-intelligence showed the extraordinary lengths the Soviet high command was prepared to go to if the city fell.

The documents were drawn from archives of the so-called"Moscow Plan" drawn up in the Autumn of 1941, when German forces were within 19 miles of the city.