Activists have accused the Russian government of erasing Gulag victims from memory after it was revealed that agencies were destroying Soviet prisoner records under a secret decree.

The director of Moscow's Gulag museum complained to Mikhail Fedotov, the head of Vladimir Putin's human rights council, that the interior ministry has been trashing irreplaceable cards containing the names of those repressed.

Mr Fedotov said archival materials must be preserved as a “means to prevent the falsification of history”.

The Soviet obsession with bureaucracy meant that careful records were kept even as judges convicted millions of people to be shot or sent to the Gulag in trials lasting mere minutes.

If prisoners survived their lengthy sentences in the far-flung labour camps and were freed, their case files were destroyed. Archive cards were created, however, recording their names, date and place of birth, what camps they had been in and when they were liberated.

But it has emerged that a secret 2014 decree signed by 11 government agencies allows officials to dispose of a prisoner's card after his or her 80th birthday. This applies to a huge number of victims, as Joseph Stalin's Great Purge began in 1936.

In response to a researcher's request for information about the Gulag sentence of Fyodor Chazov in the eastern Magadan region, the interior ministry there said his archive card had been destroyed and noted the decree's stipulations.