Openly gay actor Sir Ian McKellen joined hundreds of protesters outside the Russian embassy in London to voice anger against a “purge” of gay men in Chechnya.

McKellen described it as “a matter of principle” to demonstrate outside the Kensington Gardens consulate on Friday to demand that Moscow takes decisive action against those responsible for the brutal persecution.

Despite international condemnation, Chechen and Russian authorities have denied the accusations, according to Amnesty International. A Chechen spokesman even refuted that gay people even lived in the region.

Condemning the stance of Chechen authorities on gay people, McKellen said: “It is possible to think that gay people don’t exist because gay people are so frightened that they daren’t say they exist.

“What a condemnation it is of Chechnya that its authorities should believe that there are no gay people there, and if there were they shouldn’t be – it’s absolutely appalling.

“If gay people are invisible it’s because they are frightened to be themselves and come out, so it’s a condemnation not of gay people but the society they are trying to exist in.”

“Our principles are shared across borders, and the plight of the gay men in Chechnya is the plight of gay men and women throughout Russia.”

Reading a message from the Russian LGBT network to the crowd, he said: “Right now we need you to demand justice, we need you to tell your governments to take action, we need you to accept refugees, we need you to call for a transparent and just investigation that is going to hold those responsible to account.”

After the protest, McKellen laid rainbow roses on a rainbow flag – the symbol of the LGBT movement – outside the embassy.