The president of the English Chess Federation says he was barred from presenting prizes at the British chess championships in Sheffield because he was wearing a gay rights T-shirt [see footnote].

CJ de Mooi, an actor and a regular on the BBC quiz show Eggheads, said he was left "shaking with fury" over objections to the shirt, which bore the slogan "Some people are gay, get over it", used by gay rights group Stonewall.

De Mooi said he was approached by the championship arbiter, Lara Barnes, prior to the awards ceremony and urged to reconsider his outfit. "They then suggested that it might be better if I just presented prizes to the adults," he said. "I refused. I was either going to present all the prizes or none at all."

Barnes denied asking de Mooi to change his shirt, saying she had merely expressed reservations. "I didn't think that promoting gay rights, which I thoroughly agree with, while presenting prizes to junior chess players was an appropriate thing," she said. "Usually prize-givers for a national event would wear a suit and tie."

De Mooi said he had worn the T-shirt throughout the event without complaints. "None of the parents, none of the kids, said anything to me that wasn't completely positive. Quite a few of them said, 'we love the T-shirt, well done for wearing it'."

Laura Doughty, deputy chief executive of Stonewall UK, said she was puzzled by the furore. "We think our T-shirts are lovely and don't see why anyone would object to anyone wearing one, least of all chess players."

Leonard Barden, the Guardian's chess correspondent, said: "There has never been a dress code before. It's not something that happens in chess, it's supposed to be non-discriminatory."

De Mooi, who has been president of the English Chess Federation for the past two years, said he was angered and baffled: "I was elected president in the first place because English chess was in the absolute doldrums. As a very prominent member of the chess committee has said, I was elected because I do things differently."

Barnes praised de Mooi's efforts to promote chess but said it was improper to mix the game with gay rights: "I've every sympathy with his cause, but I didn't think it was appropriate to have the sentiment on the T-shirt in every photograph with junior chess players – under-10s, under-12s and under-14s – promoting a particular sexuality."

• This footnote was appended on 5 September 2011. The following notice was posted on the English Chess Federation's website on 8 August 2011: "There was a discussion just before the prizegiving at the highly successful Darwin Strategic 98th British Chess Championships on Saturday 6 August in Sheffield between CJ de Mooi (ECF President) and Lara Barnes (an ECF Senior Arbiter). This led to an unfortunate misunderstanding which has attracted a certain amount of media and other unwanted attention. This misunderstanding has now been resolved amicably. For our part we wish to reaffirm our confidence in CJ de Mooi as President of the ECF and Lara and all the administrative team of the British Chess Championships, who did a magnificent job as always."