The Metropolitan Water Board was formed in 1903 to take over the management and supply of water to the Greater London area. It had its headquarters and laboratory facilities in Islington, North London.
In the run-up to World War 2, the MWB recognised the risk to staff and built air raid shelters for its staff. One of these was a large shelter - divided into two main rooms - for the staff of the Laboratory Building. The shelter is accessed by an external doorway into a staircase and a further secure door.
The MWB was abolished in 1974 and its function taken over by Thames Water. The building was sold off in the 1990s and converted for residential use. The shelter was split and each was apportioned to a ground floor flat and they are now in private ownership. The connecting door between the two rooms has been sealed.