Thames House
Thames House is an office development in Millbank, London, on the bank of the River Thames adjacent to Lambeth Bridge. It has served as the headquarters of the UK Security Service, commonly known as MI5, since December 1994.

History of the building
The building was constructed in 1929-30 by John Mowlem & Co on riverside land cleared after the disastrous 1928 Thames flood severely damaged run-down residential properties. It was built to designs by Sir Frank Baines, of the Government's Office of Works. It is a uniform but not identical design to Imperial Chemical House which is opposite it on the north side of Horseferry Road; while Imperial Chemical House was exclusively for Imperial Chemical Industries, Thames House originally had various uses, including the London headquarters of International Nickel Ltd. Baines' design owes much to the 'Imperial Neoclassical' tradition of Sir Edwin Lutyens and deliberately ties in with the Imperial design of Lambeth Bridge when it was redesigned from 1929. High up on the frontage are statues of St George and Britannia sculpted by Charles Sargeant Jagger. It was owned by Thames House Estates until it was sold to the British Government in 1994. Thames House Estates was jointly owned by ICI and Prudential for many years and subsequently was wholly owned by ICI.

As 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, became vacant and it was decided to convert and refit 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). Up until series 7, the BBC television series Spooks used the exterior and lobby of the Freemasons' Hall in Great Queen Street as a location for the show's portrayal of Thames House. Since then Thames House is used although Freemasons' Hall is still used to show the entrance to the building. The third series of the BBC television series Torchwood used Thames House as the setting for the arrival of an alien species to Earth.