The coded message that arrived in Moscow’s secret intelligence HQ in 1941 was crystal clear. “Hitler intends to invade the Soviet Union,” it said.

Soviet intelligence bosses shook their heads. “Unbelievable!” they scoffed. That too was the view of Josef Stalin. On his advice no action was taken on the dire warning.

The source of the message was the legendary Soviet super-spy Richard Sorge, who had been right about so many things in the past that he should have been taken very seriously. Had he been listened to on this occasion Germany’s invasion of Russia might have been quickly repelled.

Born in Russia, Sorge studied in German universities. In 1933 the Russians sent him on a spying mission to Japan, where he posed as a German journalist. As a Russian spy he actually joined the German Nazi party – hence he learned of the attack on Russia. He was also able to tell the Soviets of the impending Japanese attack on Pearl Harbor.

Then information he transmitted to Moscow that Japan was not contemplating an attack on the Soviet Union in the east enabled the Russian Army to deploy Siberian troops for the defence of Moscow.

During the early years of the war the Japanese secret service started to intercept Sorge’s messages. He was arrested on October 18th, 1941, four days after another spy, Ozaki Hozumi, with whom he worked, was arrested. Both men were hanged on Tuesday, November 7th, 1944.