In the late 19th and early 20th centuries, swimming was a spectator sport. Onlookers lined the edges of municipal swimming baths to watch feats of endurance swimming, “underwater ballets”, and to marvel at high dives. Celebrities such as Captain Matthew Webb, fresh from conquering the English Channel, and Annette Kellermann, later dubbed the Million Dollar Mermaid, thrilled the crowds.

Step forward in time to 2017 and my visit to Thames Lido. I am here in a beautifully refurbished Edwardian swimming pool, swimming up and down what is effectively a glass box, as people sit eating their breakfast behind a vast glass wall. I splash around in front of them feeling like I’m back in a different time. Every now and again diners look up from their cappuccinos and lazily cast their eyes towards the water – and me.

It feels a slightly amusing juxtaposition. As I swim, I wonder if maybe I should be doing something more entertaining: a few handstands perhaps, or some synchronised swimming, a demonstration of the Australian Crawl? Instead I’m a sensibly clad “serious” swimmer complete with cap and goggles, sauntering up and down with a lazy front crawl – up and down, up and down. I’d feel much more self conscious if I didn’t know that I am undoubtedly having a better time than they are.

Thames Lido is special. The lidos we know and love in the UK, built mostly in the 1930s, are generally expansive and spacious. They have room for sunbathing and socialising, wide vistas and low walls. And redolent of ocean liners, they let in light and sun and fresh air and are for crowds and cavorting. They speak of holidays and sunshine and sociability and fitness.

However, this place – once the Ladies Swimming Baths in Reading’s Kings Meadow, built in 1902 – is surprisingly different. It was designed in a less showy era, as a haven for private women-only swimming. It was a secluded and closed affair: with red brick walls two storeys high, with no windows to allow outsiders to peer in. The lido walls wrap the pool like arms protectively encircling a secret heart.

Having heard about the opening, I was initially sceptical. I love the idea of the democracy of swimming. I love public pools and lidos. I was prepared to sneer and moan about the place and my swim, about elitism and snobbery – as many critics of this place have already.

But as soon as I walked in the front door, I fell in love. I swam at 7.30 in the morning, alone, on a grey rainy day, in the clean fresh water of the 25m, blue-italian-tile-clad infinity pool, in the glass walled courtyard. Steam gently rose from the water, which is heated to a cool 25C – perfect for swimming. I thought it might feel chilly, but there was no wind in this protected courtyard. It has a beautiful outside-yet-inside vibe: nestled away, while overhead the sky and the leafy tops of tall trees peeked over the walls. Every now and again a gust of wind would catch the branches and a few autumn leaves would flutter down delicately into the space and scatter themselves artfully on the pool. I was in heaven.

Facebook Twitter Pinterest Thames Lido bar. Photograph: Sally Goble

The Thames Lido team has done a great job. The facility had fallen into disrepair after years of neglect by local councils. Unused since its closure in 1974, the lido’s future hung in the balance until the team behind Bristol Lido rescued it. After discovering it in 2012, they began the painstaking refurbishment of the grade II listed building, finally opening the doors last month. The restoration has been sympathetic; the showers, the massage rooms and the sauna facilities are straightforward and have a quirky Scandi feel to them – as does the “shower naked” policy that swimmers are encouraged to adopt before they swim. The poolside restaurant is airy and bright, the food delicious.

As I’m shown around the place, Mark Thwaites, one of the directors of the company behind the Lido, refers to the place as a “lee-do”. When I ask him about his preference for lee-do over lie-do, he describes his childhood memories spent playing in Guildford lido (very much a british lie-do) – all floating plasters and kids splashing and soggy sandwiches. He likes to think that Thames Lido has a more glamorous European vibe to it, hence the pronunciation. I see where he is coming from: it’s a grown-up version of a lido, a place to feel pampered and cosseted, to relax and retreat, and to be well fed, a million miles away from the every day.