Campaigners have slammed the Natural History Museum for hosting a reception for the Saudi Arabian embassy.
They have said hosting the event will “taint” the museum because of the regime’s involvement in the war in Yemen.
The Saudi-led coalition has been engaged in fighting in Yemen for more than three years.
Although it is almost impossible to confirm the numbers some 50,000 people are understood to have died there.
While a UN group of experts recently reported that war crimes are likely to have been committed by all sides in the conflict.
It comes as controversy surrounds the disappearance of journalist and Riyadh critic Jamal Khashoggi, who was last seen going into the Saudi embassy in Turkey nine days ago.
Turkish officials claim that Mr Khashoggi was murdered within its walls. Saudi Arabia denies this.
But the museum say they need to host such events to “maintain our position as a world class scientific research centre and visitor attraction”.
Earlier this year the Tory Party held their Black and White fundraising ball there.
While in 2012 the Museum hosted the reception for the Farnborough Intrernational Airshow, a major arms fair that brought many of the world’s biggest arms companies together with repressive regimes from around the world.
Andrew Smith of Campaign Against Arms Trade said: “The Natural History Museum is a very prestigious venue, and should not be hosting a regime which has been accused of killing journalists and is inflicting a humanitarian catastrophe on the people of Yemen.
“The Saudi authorities have a contempt for human rights, and events like this will undoubtedly be regarded as an endorsement. It’s time for the Museum to take a stand.”
Sayed Ahmed Alwadaei, Director of the Bahrain Institute for Rights & Democracy said: “Hosting the Saudi embassy so soon after the alleged murder of a dissident journalist will taint the museum’s reputation. Conducting business as usual with the Saudi regime normalises its crimes and emboldens it to continue its policy of repression and abuse.”
A spokesman for the Museum said: “The Natural History Museum was booked by the Saudi embassy over two months ago as a venue for an external event to celebrate Saudi Arabia Day.
“No Museum staff are attending as guests or speaking at the event.
“Enabling commercial events to take place outside of public opening hours in our iconic spaces brings the Museum an important source of external funding, which allows us to maintain our position as a world class scientific research centre and visitor attraction.
“We hold a wide variety of commercial events and it is made clear to any host that doing so is not an endorsement of their product, service or views.”