One of the most exclusive, all- male golf clubs in Scotland has vowed to continue its ban on women despite growing pressure from politicians and an angry outburst from former prime minister Gordon Brown.

The Honourable Company Of Edinburgh Golfers at Muirfield in East Lothian refused to budge on its ban just days after a dramatic announcement from Augusta National Golf Club that it was ending its 80-year gender barrier.

The home of the Masters golf tournament, famed across the world, said it was to admit two women, Condoleezza Rice and Darla Moore, to its erstwhile 370-strong all-male membership within weeks.

Despite the growing row, Muirfield – which will host the 2013 British Open Championship next summer –- is defiant about remaining one of the last bastions of all-male traditions.

The club came under attack last week from deputy Labour leader Harriet Harman, who branded it old-fashioned and out of touch.

She said: "It's completely wrong that Muirfield is still men-only, especially after a brilliant summer of women's sport. If Augusta can open its doors to women members, it would be embarrassing if Muirfield didn't follow suit."

But it was an attack by former prime minister Brown that will put most pressure on Muirfield and the Royal And Ancient Golf Club in St Andrews, which also refuses to admit women members.

Brown called the stance an "unacceptable blot" on Scotland's traditions of "justice for all" as he gave a speech to the Festival of Politics at the Scottish Parliament on Friday. He said: "I think we've got to think hard and long about issues of discrimination in our own country where we've got to tackle inequality and tackle that injustice.''

The Scottish Government is also among those calling for all-male golf clubs to admit women, but the Royal And Ancient, Muirfield, Royal Troon and others appear to be sticking to their guns.

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Yesterday Alastair Brown, the secretary at Muirfield, said the club had no plans to either change its membership policy or bow to public pressure on the matter.

"The state of the membership of Muirfield is a private matter for the members to decide," he said. "It is not an issue for the outside world.

"Single-gender clubs cannot be classed as discriminatory. It is simply the freedom of people to keep their own company – men or women. The Equality Act is very specific – it allows for gender-only private clubs. It comes down to this issue again: are men and women clubs not allowed to keep their own company?

"Are you not allowed to have a ladies' gym club? Are you not allowed to have a ladies' bridge club? As the law stands at the moment, yes, you are, and I see no sign of that changing.

"There will be no imminent change here at Muirfield. To the best of my knowledge it is not even on the agenda."

Muirfield's Brown said he was aware of the statement from Augusta National last week, but insisted the Scottish club differed in a number of ways from Augusta, not least in its openness to women visitors. Muirfield, in fact, claims to be among the most open and welcoming to women guests and visitors of all the private, men-only clubs.

"I read of the Augusta National development with interest, but at Muirfield we differ from them in a number of ways," he said.

"Although we are a private club, we are actually very open and welcoming to ladies. They can come and play our course any day of the week, and they can go wherever they want in our clubhouse. There are no barriers anywhere.

"We have had ladies playing at Muirfield since 1891, and they certainly don't have to be a member to play here. I think you'll find that our attitude to lady golfers is far more welcoming and hospitable than is the case in many places."

Some have argued that Muirfield's staging of the Open might come under threat because of its all-male policy, but the club secretary insisted that hosting the Open was not a critical issue for the members.

"The Open is not a huge money-spinner for Muirfield," he said. "We happily host the event because we happen to have one of the world's great golf courses here, and the Royal and Ancient want us on their Open rota.

"But it is not a big-ticket item for the club. Yes, we receive a fee for staging the Open, but our members have to do lots of work in preparation.

"I am not a member of Muirfield, I am merely the secretary. But I am trying to explain to you what the club is like here. It is most certainly not 'anti-women', as you will see any day of the week at this golf club."

Billy Payne, the chairman of Augusta National, called it "a joyous day" when the club accepted Rice and Moore into membership, having privately pursued the matter with his members for some years.

Payne said he had grown painfully aware of how out of step Augusta had become.

Some prominent Scottish golf voices have called for Muirfield and other Scottish clubs to follow suit.

Catriona Matthew, a former Women's British Open winner who is currently ranked 24th in the world, was among those who called for Muirfield to change its policy.

Matthew said: "I think it is great news from Augusta National – we need more equality in golf. My hope is that Muirfield and other male-only Open venues such Royal Troon and Royal St George's will soon follow in Augusta's footsteps."

Yesterday, the Royal And Ancient Club at St Andrews could not be contacted to comment on Gordon Brown's remarks. But chief executive Peter Dawson, has previously said there is "nothing wrong" with men-only clubs.

Three years ago he said: "It's hardly life-threatening, is it? It is just a game, after all. People play golf and have fun. Men's and women's golf coexist extremely well."

Speaking on the subject in 2007, he said: "Members of golf clubs do have the right to associate freely.

"I understand there is nothing against the law about that [men-only clubs] and as I see it, there's nothing wrong with it."