Parliament Hill Lido

Built in 1938 and refurbished in 2005, the Grade II-listed Parliament Hill Lido measures a generous 60 metres by 28 metres. It has a stainless steel pool liner (the only one in an outdoor pool in the UK) which gives the water a metallic shimmer - not that you'll be able to tell when it's packed full of people on a sunny day. The lido is unheated, but wetsuits are permitted at the lifeguard's discretion. There are two sessions a day (7-9am and 10am-6pm) with an additional adults-only evening session on Mondays, Thursdays and Fridays. There's a paddling pool for under-fives and a cafe.