The Cottonmill Spa at Sopwell House is a light-filled haven of squishy day beds, cubist fireplace blocks, and a beautiful spa garden designed by RHS Chelsea Flower Show gold-medallist Ann-Marie Powell. For spa experiences near London it’s ideal: the property is only 10 minutes from the M25, but you wouldn’t know it, save for the odd whoosh of cars barely audible over the trickling fountains, bubbling hot tubs, moon shower, and pond-like water features inspired by the nearby River Ver. Sofas, cabanas and fire pits are set around a warm indoor-outdoor pool framed by large oak trees. Inside, there are two saunas, one organic, another with panoramic views; two steam rooms, one briny, the other herby; thermal experiences and relaxation rooms. Access to the Cottonmill spa is complimentary for hotel guests, and those staying in Mews Suites receive complimentary access to The Club at Cottonmill.