Belfast Corporation built six Sub Controls between 1954 and 1956 each reporting to the Corporation main control in the former Regional War Room in Mount Eden Park. The Sub Control remained operational until the disbanding of the Civil Defence Corps in 1968 and is now used as a government document store.
The single storey concrete blockhouse is surrounded by bushes in a car park on the south side of Stormont Castle grounds and on the north side of Newtownards Road.
Those taking part in the visit were Nick Catford, Keith Ward, and Wayne Davies.