Campaigners accused the Royal British Legion (RBL) of homophobia, claiming it sought to erase LGBT people’s contributions to British war efforts.
After decades of criticism, the charity has tried to make amends.
The RBL responded to a complaint from human rights activist Peter Tatchell, who said he first wrote to the organisation in 2007.
He reminded them of this letter late last year, saying the RBL had declined to answer.
Charles Byrne, the charity’s director general, reportedly wrote back: “I am deeply saddened by your previous experience with the charity, and I can only apologise on RBL’s behalf for not responding and the discrimination shown at the time.”
Mr Tatchell, the Guardian reports, said the RBL had accused his organisation OutRage! of “making political capital” out of Remembrance Sunday.
It came after members laid a pink triangle wreath at the Cenotaph.
Mr Tatchell wrote: “Our observance of queer remembrance day was, you say, in ‘bad taste’.
“Who does the British Legion think it is? It is sheer arrogance for you to criticise and demean our act of remembrance.
“The gay community has as much right to honour its members who fought for freedom as the Black and Jewish communities, both of which pay respect to their war dead without being vilified by the British Legion.”
He claimed the RBL “lacked the decency to acknowledge the contribution of queer soldiers, sailors and aircrews to the Allied victory over Hitlerism”.
The charity was urged to “officially admit that any homosexuals fought in the last war, let alone that some of them acquitted themselves with distinction”.
Mr Byrne, though, insisted the charity has “very much changed”.
He added: “The behaviour you outline of the RBL of the past is not tolerated in today’s organisation.”
A ban on gay people serving in the armed forces was lifted in 2000.
But OutRage! claimed that an unwillingness to acknowledge the gay and lesbian people who served persisted.
Responding to Mr Byrne’s letter, Mr Tatchell said the RBL’s response “draws a line under the pain”.
He said: “Our praise and thanks to the Legion for eschewing its homophobic past with this forthright and fulsome apology.
“We are delighted by its commitment to support LGBT veterans and work with the LGBT community.
“This draws a line under the pain of the RBL’s previous prejudice and discrimination. LGBT people can now confidently collaborate with the RBL, knowing that they are on our side.”
The Cenotaph in Whitehall Dominic Lipinski
Ex-Servicemen and women commemorate the fallen Dominic Lipinski