Inside one of London's Victorian underground reservoirs

Thames Water has about 320 service reservoirs, which hold treated water before it comes through our taps.

Every 10 years individual reservoirs get taken out of service for a short period of time for maintenance and to check everything is in working order.

Crouch Hill reservoir was built in 1880 and normally holds enough water for 122,000 homes in north and east London.

Despite its age, it remains in excellent condition and is a showcase of Victorian architecture and design.