You could be forgiven for thinking that Mayfair is just for braggarts – for the flashy cars and glitzy shop windows, for the jeroboam-strewn bars and the duplex penthouses. But what’s really special about the area is what’s hidden from plain sight.

You could walk down Brook’s Mews every day without knowing that behind an understated door, painted a distinguished shade of British Racing Green, is one of the most elite sports clubs in the world.

The Bath & Racquets Club is a sports club and gym that is as distinct from your average Virgin Active as a Rolls-Royce is from a Renault. Designed by the godfather of clubs Mark Birley, this unique private members’ squash and sports club is celebrating its 30-year anniversary this year – and we had a rare look inside.

The club has just 300 members; fees are £1,000 entry and £7,500 per annum. In order to even get on the list you have to be proposed and seconded by current members of the club. And then you just have to wait – for at best emigration and at worst death before your chance to move up the list.

Bath & Racquets Club

So what do members benefit from? Well, they have a wood-panelled gentleman’s club, as if lifted straight from 18th-century Piccadilly, just five minutes’ walk from Oxford Circus. They have a state-of-the-art gym with an army of personal trainers on hand at all times. They have competition-grade squash courts cleaned daily and a number of squash professionals in residence – including a former world number two and eight. (There’s no need to bring your gym bag here, by the way – everyone wears the club whites, which are laundered for you on site.)

And, they get the changing room – the club’s real highlight. Which surely no one has ever said about any sports club. But this changing room is one like no other. It’s furnished with huge sofas; a flatscreen TV; a leather-topped writing table; and – perhaps most importantly – a fully licensed bar. It is the heart of the club – and whether you’re lounging in a club dressing gown after a tough session in the steam room, or you’re enjoying a post-massage martini, it is sports for the sophisticated.

So, why are we telling you all this if there’s little hope of you even getting inside? Well, now there is. As the in-house barbers is now offering bookings to the layman. So as well as a short back and sides, you can now get a foot – both physical and proverbial – in the door.

Bath and Racquets Club, bathandracquetsclub.co.uk; 49 Brook's Mews, Mayfair, London W1K 4EB