Thirty Seven Degrees

Although almost entirely underground, this fitness club on the banks of the Thames has such great facilities that you can easily forgive the lack of riverside views. Five studios offer classes ranging from yoga to circuit training, a boxing ring and a state-of-the-art gym with TRX suspension training equipment. There's also a spa offering treatments, a steam room, sauna and solarium. In addition, the club caters to the corporate market with classes and treatments aimed at the time-poor (do a 22-minute exercise class at lunch) and lucrative company rates. There's another branch in Kensington's Olympia.