11/01/2013 09:06 am ET Updated Jan 23, 2014

London Hotel Luxury: The Connaught Enters The 21st Century With Its Subterranean Swimming Pool And Spa

Over the years, Jackie and I have been lucky enough to stay in some pretty swell hotels (and plenty of cheap dumps too). I can't name a favorite - how do you choose among places like, say, Le Bristol in Paris and the Park Hyatt in Tokyo? - but toward the very top of any list would be The Connaught and The Berkeley, both in London.

Before its 2007 renovation, The Connaught was a paradox. Staying there was among a traveler's most pleasant experiences, a happy mixture of grand formality and domestic coziness. Its "home away from home" catchphrase really captured the spirit of the place. The paradoxical part was that in many respects the hotel was in a terrible state of disrepair: well polished to be sure, but dented, chipped, frayed and technologically outmoded. But no one cared; to stay at The Connaught was to love the place and to love the people who worked there, starting with the general manager, who always seemed to be in the lobby to greet guests by name.

It's a much more consistently luxurious hotel now, entirely up to date but with its charming old bones (and at least some of its beloved old furniture) still apparent. It definitely remains a hotel to love. Now, if you're going to be a luxurious hotel in the 21st century, you need somewhere for guests to swim and steam and be massaged: a tall order in an Edwardian building in crowded Mayfair. The solution was to dig deep under the extension opened in the second phase of the renovation and install a spa and what may be the most relaxing swimming pool ever. (The Berkeley has always had a nice rooftop pool with gorgeous Hyde Park views - it has recently been refurbished and a Bamford Haybarn spa added: very rus in urbe. On warm, sunny days they open the retractable roof and it's like being ... well, it's certainly not like being in Knightsbridge.)

We hadn't stayed at The Connaught since its spa opened in 2010, and when we were last in London we paid a visit to have a look.

Down in the second basement, the pool - at about 10 meters (33 feet) in length not huge, but pretty good for the middle of Mayfair and more than sufficient for recreational swimming - is unimaginably peaceful, in part because it is so subterranean. It is lined in black stone with intermittent white strips to help you swim in a straight line (and for beauty's sake), and the water thus takes on a shadowy, almost mysterious quality. At one end is a ridged double-height stone wall down which a waterfall plays, creating a steady gentle sound conducive to calm. Light filters through lovely pierced screens which remind me of Moghul India, though I'm not sure that's what was intended. There's a steam room just off the pool deck with little points of electric starlight set into the ceiling: perfect for two or three minutes of serious sweating before a quick return to the pool.

The water is disinfected using a non-chlorine system, so there are no chemical odors to interfere with the aroma of the delicious ginger or lemongrass infusion you will be offered after your swim.

The spa is operated by Aman Resorts, the first outside their own properties. Treatment rooms are similarly serene, and the staff we met were charming and welcoming. There's a lot of what I see as pan-Asian hocus-pocus in the way the treatments are described - references to qi, meridians, chakras and what not - but there's no harm in that unless you think it is going to cure you of a major illness, and I can put up with a bit of energy-harmonization if it is pleasant and relaxing. The fact is, though, that there are recognizable treatments like massages (albeit "holistic" ones) and body scrubs.

Unless you're staying at the hotel - which you should try to do at some point in your life - it is a spa treatment that will enable you to enjoy the pool and the steam room, because day passes are not available to non-guests.

After our lovely swim, rather than getting our vital juices purified, Jackie and I headed up to the hotel's Coburg Bar, where we had stellar cocktails and two bowls of perfect potato chips: easily as restorative as a Himalayan crystal salt body scrub, don't you think?

The Connaught.
Carlos Place, London W1K 2AL; +44 (0)20 7499 7070;; Aman spa: +44 (0)20 3147 7305; Depending on date and availability, rooms start at about $565; spa treatments start at £80 ($130).

The Berkeley. Wilton Place, Knightsbridge, London SW1X 7RL; +44 (0)20 7235 6000;; Bamford Haybarn spa: +44 (0)20 7201 1699; Depending on date and availability, rooms start at about $450; spa treatments start at £55 ($88).

London Hotel Luxury: The Connaught's Aman Spa