The Foreign Office began last week trying to trace relatives of the two men, named as George Hanna and William Wileden. They were said to have gone to Russia as activists 60 years ago, but later to have been shot or died in the camps.
The Russians, however, not for the first time, appear to be indulging in an excess of self-criticism. It is not true that both men died at the hands of Stalin's security officials. One of them, George Hanna, survived years in labour camps and died a natural death in Moscow.
Friends and colleagues recall him working as a translator - living in a small flat in central Moscow during the 1950s and 1960s - after his release and rehabilitation. He died in about 1962, when he was aged about 60, apparently from natural causes, although his death may have been hastened by years of ill-treatment.
The second man, named as William Marshall Wileden, born in 1892, remains a mystery. According to the Russians, he was sentenced to death and shot. There was no immediate corroboration.
Both men are believed to have gone to Moscow in the 1930s as activists for the Comintern, the Communist International, the Soviet-led international organisation which preached world revolution. It was wound up in 1943.
Hanna's origins and background are unknown. He worked as a translator at the Foreign Languages Publishing House and later for Radio Moscow. Friends are uncertain about the exact date of his arrest, although most think he was imprisoned in the late 1940s and spent about 10 years in prison, rather than the 20 years claimed by the Russians.
He was released in 1957 after pressure from leading British Communists, and chose to return to his life in Moscow.
Sam Russell, 77, then Moscow correspondent of the Daily Worker, met Hanna in Moscow at the 'coming out' party on his release, held at the Astoria in Gorky Street. 'He was a nice man. He was very pleased to be out, but didn't want to talk about the camp very much,' he recalled.
But Hanna did describe his arrest in the middle of the night and subsequent interrogation by secret police, who accused him of spying. He described his inquisitors' reaction when he cited Harry Pollitt, general secretary of the British Communist Party, as a friend who would vouch for him: they looked Pollitt up in a black book and said he too was a British government agent.
Denis Ogden, 65, who worked alongside Hanna at the publishing house and later succeeded Mr Russell as Daily Worker correspondent, recalls Hanna well.
'I remember asking him what he thought when he was arrested. He said he thought there had been a mistake which would be corrected. He went on believing that until he got to Irkutsk, when he realised there were hundreds and thousands of other people on their way to Siberia,' Dr Ogden said.
Hanna married an American, Rosie, who died in Moscow shortly before he did. His only known relatives are two daughters, Lucy and Eileen, who are now likely to be in their fifties and are thought to be living in England.
The name of a third previously unknown victim of Stalin's purges was revealed to the Independent on Sunday last week by Dr Ogden. He was Bernard Isaacs, who also worked for the Foreign Language Publishing House and was imprisoned in camps twice, for a total of about eight years. He died in Moscow in the late 1950s or early 1960s.
The disclosures bring the number of British civilians known to have been imprisoned by Stalin to at least five.
Another mystery of Stalin's persecution is the fate of Rose Cohen, an Englishwoman married to a senior Russian party official, Petrovsky. She was arrested in 1938, accused of spying and sent to a labour camp. She was never heard of again.
Len Wincott, a sailor who took part in the Invergordon Mutiny in 1931, went to Russia and was imprisoned in Siberia between 1944 and 1954. He subsequently wrote a book about his experiences and died in Russia in the 1980s.
Two weeks ago the Russian Security Ministry disclosed that two serving British servicemen, Michael McKay, a pilot, and Gerald Phillips, a reconnaissance officer, had been imprisoned by the KGB during the 1950s and 1960s.