A Catholic member of a Freemasons Lodge in Belfast has said he is prepared to quit over plans to hold a celebration dinner for the Ulster Defence Regiment.
The long-term member, who wished to remain anonymous, told the Belfast Telegraph he felt hurt when letters were issued from a number of lodges to encourage ticket sales.
The fraternal organisation is open to all religions, with members agreeing not to discuss religion or politics.
The event will be held in May at a hotel in Carrickfergus, marking 50 years since the formation of the UDR.
A spokesperson for the Belfast Masonic Charity said the event was organised by several members acting in a private capacity and was not officially endorsed by the Masons.
Explaining his reaction, the person said: "This has shocked me because, first of all, the UDR are steeped in controversy over the years just like the paratroopers. The Freemasons should not be getting involved in this.
"The other thing is that provincial grand lodges of Antrim and Down have given their backing by sending letters out to lodges with a directive to support this event."
He continued: "I'm not bigoted, many in the UDR did a great job, but we should not be getting into bed with this organisation.
"I'm a Roman Catholic and I go to chapel, now people are going to say 'you're backing this'.
What has happened over the last two weeks when this letter came out, this directive, it has shown me the sectarianism developing inside the Freemasons
"It's made me very uncomfortable and a lot of Freemasons have called me to say they feel the same."
He said he first joined the Freemasons for friendship and camaraderie, with all religions and professions represented.
"Catholic, Protestant, Jewish. You name it, they're there," he said.
"I enjoyed everybody's creed, but we don't talk about religion. We meet with the call 'on the level', everybody's the same.
"Whether you're a bank manager or a street sweeper, Catholic or Arab, we're all the same brothers.
"But now what has happened over the last two weeks when this letter came out, this directive, it has shown me the sectarianism developing inside the Freemasons.
"We should not be involved in any politics.
"If the UDR applied to the charity for a grant, for something like children and widows suffering hardship, that's different.
"To me that's an appeal for help. But when you're talking about throwing yourself behind a celebration dinner it makes no sense."
He said many Catholics still viewed the Freemasons as taboo, incorrectly believing it to be associated with Protestant organisations like the Royal Black Institution.
"If this comes out my chapel is going to react (badly), there's four Freemasons in my chapel," he said.
"My wife said to me it might be time to resign. If they go ahead with it, I will not be a member come May.
"It's the backlash I fear for my family and other Catholic members who are going to face the same blinded view of the organisation.
"That's the fear."
Billy Beattie, secretary of the Belfast Masonic Charity, disagreed that the Freemasons were backing the event.
"The Freemasons aren't actually running the event. As I understand it's some of the masonic veterans who were members of the UDR and there's no proceeds going towards the masonic charities," he said.
"I think he's possibly misinterpreted it, but I'm happy to take a phone call if he wants an explanation.
"From our perspective, we're a long-established charity and I can assure you there is no religious or political bias as regards our charities."