Thames House - MI5 and NIO Headquarters

MI5 and NIO Headquarters

The dispersed and dilapidated state of its previous buildings in Curzon Street House (since demolished) and 140 Gower Street (also demolished) led MI5 to seek a new home in the late 1980s. The Secret Intelligence Service (MI6) were engaged in a simultaneous hunt for new headquarters and consideration was given to co-location of the two. However this proposal was abandoned, due to the lack of buildings of adequate size (existing or proposed) and the security considerations of becoming a single target for attacks. At the same time, Thames House, which was largely used as government offices by then, became vacant and it was decided to convert and refit much of it for MI5's use. The GMW Partnership undertook the design and Mowlem carried out the necessary reconstruction work from 1990, which included part-infilling of the building's distinctive archway.

The building is shared with the Northern Ireland Office (NIO).