ONEof the greatest fixtures in the British sporting calendar got under way yesterday.

The Open Championship is the biggest and best golf tournament in the world, but rather than the focus being on if Tiger Woods will triumph or whether Britain's own Justin Rose will win two majors in a row much of the build-up has been quite rightly focused on the sexism that still exists in some quarters of the sport.

As we come up to the 'one year on' anniversary of the London 2012 Games, we have over a million more women and girls playing sport and to continue that trend we need to ensure that the perception of, commentary on and attitude towards female athletes – and women's sport generally, are as positive and inclusive as possible.

Muirfield's policy to have no women members is anachronistic, outdated and sends completely the wrong message at a time when we should be doing all we can to encourage more women to play sport.

Muirfield argues that it is a private members club and it's up to them who they admit, but their policy of discrimination against women is indefensible given the public role they play as hosts of the Open Championship.

The R&A, as the governing body of the sport, needs to act.

The greatest tournament in golf should not be allowed to be staged at men-only clubs. If the R&A had a policy that said the Open Championship had to be staged at clubs that had both men and women members, surely Muirfield, Royal Troon and Royal St George's would respond and accept women.

Would they really want to be off the Open Championship rota, given the history they have with the event and the exposure it gives to their courses?

The R&A does do a lot of good in promoting the game to young men and women around the world, but on this issue they have had their head in the sand for too long.

The R&A chief executive Peter Dawson said two days ago that this is a "difficult" issue for the R&A but the solution is a very simple one and I hope they don't merely kick the matter into the long grass – or perhaps 'the rough' is a more appropriate phrase – when the Championship rolls out of Muirfield on Sunday.

Two times major winner Rory McIlroy was right when he said this week that men-only clubs "is something that shouldn't happen" and that "it's something we shouldn't even be talking about". I couldn't agree more.

I hope that in the imminent future we're not talking about it. And then the focus can be all about the golf.

l Maria Miller is Conservative MP for Basingstoke and Westminster Culture Secretary.