The Imperial War Museum has been criticised for allowing a German company connected to the Nazi death camps to fund a major international conference.
The three-day "Beyond Camps and Forced Labour" seminar, due to be held in London in January, will bring together academics studying the effects of Nazi atrocities on survivors.
But Holocaust survivor and academic Michael Pinto-Duschinsky said it was immoral for the museum to accept funding from Degussa, whose original parent company, Degesch, was involved in the production of the Zyklon B gas used to kill Jews.
It also extracted and smelted gold teeth from camp victims.
But a museum spokeswoman said accepting the funding, whose figure is unknown, was "entirely legitimate".
Organisers of the conference include Jewish historian David Cesarani and Suzanne Bardgett, who oversees the museum's permanent Holocaust exhibition.
In 2004, Degussa was forced to pull out of a contract to provide graffiti-proofing chemicals for Berlin's Holocaust memorial.
And in 1998 the company agreed to make payments to Auschwitz survivors who worked as slave labourers in a tyre factory it ran during the war.
Further funding for the "Beyond Camps and Forced Labour" conference is being provided by the German and Polish embassies, the Austrian Cultural Forum, and the London-based German Historical Institute.
Calling on the museum to return the money, Dr Pinto-Duschinsky said: "Important questions of public policy and of community relations arise from this. I agree with the members of the Berlin Holocaust Memorial who felt that it is unsuitable, not to say ghoulish, to accept funding from the profits of the manufacture of Zyklon B or of smelted tooth gold for Holocaust exhibition or memorial purposes."
A museum spokeswoman said: "It is entirely legitimate for a small proportion of the overall funding to come from a modern-day corporation which has looked critically at its own past.
"The 2009 conference is a follow-up to two successful conferences which took place in 2003 and 2006."
Evonik Industries, Degussa's current parent company, said it accepted responsibility for events in its past and wanted to support the conference, to raise awareness that "the Holocaust did not end with the liberation of those who survived" and has had a severe impact on subsequent generations.