MI5 - Security Service

Thames House

The Security Service has its headquarters at Thames House, a Grade II listed building at the corner of Millbank and Horseferry Road in central London. It overlooks Lambeth Bridge, a few hundred yards south of the Houses of Parliament on the north bank of the Thames.

Thames House
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The Secret Intelligence Service's distinctive "ziggurat" building at Vauxhall Cross, which is often mistaken for the Security Service's headquarters, is located on the other side of the Thames near Vauxhall Bridge.

Design and construction

Thames House was designed by Sir Frank Baines, the Principal Architect of the Government's Office of Works, and constructed in 1929-30. It was built on the site of a poor, run-down district that was widely regarded as a slum (in the words of The Times, "a reproach to Westminster").

Thames House
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The area was devastated by the Thames flood of 7 January 1928, in which 14 people died. Following the flood, the damaged properties on the site were demolished, freeing up a large area of land for redevelopment.

Thames House was built at the same time as a number of other office buildings in the Millbank area. Its design is similar - though not identical - to that of Nobel House on the other side of Horseferry Road. The two buildings were constructed at the same time to serve as headquarters for Imperial Chemical Industries Ltd (ICI). Nobel House is now occupied by Ofgem, the Office of Gas and Electricity Markets.

The design of Thames House owes much to the Imperial Neoclassical style of Sir Edwin Lutyens, the designer of the Cenotaph on Whitehall. It also ties in with the Imperial design of Lambeth Bridge (built 1930-32). The Portland stone façade is decorated with sculptures by Charles Sargeant Jagger, a prominent British sculptor of the early 20th century, who also designed the Royal Artillery Memorial at Hyde Park Corner.

The facade of Thames House displays a number of inscribed coats of arms with Latin mottos that reflect the building's location and history prior to it becoming the Service's headquarters. These represent the City of Westminster ("Custodi civitatem domine", "Lord protect the citizens"), the City of London ("Domine direge nos", "Lord, guide us") and the Port of London Authority ("Floreat imperii portus", "May the gateway of the Empire flourish"). The Service's own crest and motto are displayed in the flag flown from the roof of Thames House.

The building's impressive riverside location and advanced internal features led to it being described in the 1930s as "the finest office building in the British Empire". Its letting agents described it as "represent[ing] the last word in modern business efficiency." However, the design was not universally praised; the architectural historian Sir Nikolaus Pevsner wrote of his dislike for Thames House's "nasty cheese-coloured roof."


Thames House originally consisted of two separate blocks linked by an archway across Page Street. Before the Second World War, it was occupied by ICI and a variety of other tenants, including the Warburg Library (now the Warburg Institute), the International Nickel Company of Canada and the Liberal Party leader David Lloyd George. The building was used as an air raid shelter during the war, with local residents sleeping in the basement while the Luftwaffe bombed Westminster.

By the mid-1980s, Thames House was occupied by ICI (in the north block) and the Department of Energy (in the south block). The Security Service was at this time housed in a number of different buildings around London. It was decided that new accommodation would be needed in order to provide a better working environment for staff and to cope with new requirements such as modern IT systems.

The two blocks were acquired by the Government at the end of the 1980s and were extensively refurbished for use by the Security Service. Some major structural changes were made, such the construction of a new link block between the two formerly separate wings of the building. The refurbished Thames House was officially opened on 30 November 1994 by the then Prime Minister, John Major MP.

It should be noted that the building that represents the exterior of Thames House in the TV series Spooks (or MI-5) is a different building altogether. Spooks' version of Thames House is actually Freemasons' Hall in Great Queen Street, Covent Garden, and the interior depicted in the series is a studio set.

Because of security considerations, we do not offer public tours of Thames House.

Suggestions for further reading on Thames House

  • The Face of London. Harold Philip Clunn, 1951 (Phoenix House)
  • London 1: The Cities of London and Westminster. Sir Nikolaus Pevsner, 1957 (Penguin)

Key points

  • Built in 1929-30 on Millbank, central London.
  • Originally an office block used by ICI and other organisations.
  • Became the Security Service's HQ in 1994.

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