The Armistice of November 1918 ended four years of slaughter that left armies exhausted and populations weary of war – but the fighting was not over. In Russia, civil war and revolution had divided the nation and the Allies sought to intervene on behalf of the ‘White’ Russians against the Bolsheviks and this conflict continued long after the war had finished elsewhere in Europe.

A vital source of information from inside the Bolshevik-held territory came from British secret agents in Petrograd, the main one being Paul Dukes. Known as the ‘Man of a Hundred Faces’, Dukes had managed to infiltrate both the Communist Party and the political police. The problem which faced the head of the British Secret Intelligence Service, Maurice Smith-Cummings, was getting Dukes’ information back to London. Carrying information overland was proving far too problematical, so Smith-Cummings hit upon the idea of using one of the Royal Navy’s new fast Coastal Motor Boat which was revealed just before the end of the war.

He recruited Lieutenant Augustus Agar and through him he found five men, all unmarried, who could handle the two CMBs. Using an inlet on the Finnish coast as a base, Agar slipped past a series of forts, submerged breakwaters and the Russian Baltic Fleet to reach Petrograd and made contact with Dukes. A frequent courier service was soon established, with Agar carrying couriers in and out of Petrograd under the very noses of the Russians.

So confident did Agar become, he even torpedoed the Russian cruiser Oleg. He followed this with support from Admiral Sir Walter Cowan in an all-out raid upon the Russian ships with eight larger CMBs and a bombing raid by the RAF. The raid resulted in the sinking of two battleships and the submarine depot ship Pamiet Azova.

Agar was quietly given the Victoria Cross but told not to publish his memoirs until 1963. As for Paul Dukes, his cover was eventually blown, and he had to escape via Latvia in a number of hair-raising escapades. In 1920 he was knighted by King George V, who called Dukes the ‘greatest of all soldiers’. To this day, Dukes is the only person knighted based entirely on his exploits in espionage.

This is their remarkable story.