Thames House is an office development in London on the bank of the River Thames adjacent to Lambeth Bridge. It has served as the headquarters of the British Security Service agency, commonly known as MI5, since 1992.

MI5 headquarters at Thames House, seen from the Lambeth side of the River Thames.

The building was constructed in 1929-30 to designs by Sir Frank Baines, of the Government's Office of Works. It is a uniform but not identical design to Nobel House which is opposite it on the north side of Horseferry Road; while Nobel House was exclusively for Imperial Chemical Industries, Thames House had originally various uses. 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 by C.S. Jagger.

The archway, showing the GMW infill extension built for MI5.

As MI5 headquarters

The dilapidated state of its previous headquarters in Curzon Street House (since 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 providing a single target for attacks. At the same time, Thames House, which was largely used as government offices, came vacant and it was decided to convert it for MI5's use. The GMW Partnership undertook the necessary reconstruction work from 1990, which included part infilling of the archway one third down the building.

Thames House now stands almost opposite the headquarters of its sister organisation MI6, at Vauxhall Cross.

See also

• SIS Building - Headquarters of MI6