Built between 1940 and 1942, eight deep-level air raid shelters are located 180 steps below ground and under the Northern line tunnels at the south-east corner of Clapham Common, opposite Clapham South Tube station.
Each shelter consists of a pair of parallel tunnels 16 feet 6 inches (5.03 m) in diameter and 1,200 feet (370 m) long. Each tunnel is subdivided into two decks, and each shelter was designed to hold up to 8,000 people.