Also close by are Downing Street, the Cenotaph, Westminster Millennium Pier, the Treasury, the Foreign and Commonwealth Office, and the Supreme Court.

[7] It was originally the eastern terminus of the DR and the station cutting ended at a concrete wall buffered by timber sleepers.

[8] The approach to the station from the west runs in cut and cover tunnel under the roadway of Broad Sanctuary and diagonally under Parliament Square.

In Broad Sanctuary the tunnel is close to Westminster Abbey and St Margaret's church and care was required to avoid undermining their foundations when excavating in the poor ground found there.

The service was run by the North London Railway (NLR) from its terminus at Broad Street (now demolished) in the City of London via the North London Line to Willesden Junction, then the West London Line to Addison Road and the DR to Mansion House – at that time the eastern terminus of the DR.[10] From 1 August 1872, the Middle Circle service also began operations through South Kensington, running from Moorgate along the MR's tracks on the north side of the Inner Circle to Paddington, then over the Hammersmith & City Railway (H&CR) track to Latimer Road, then, via a now demolished link, on the WLEJR to Addison Road and the DR to Mansion House.

[12] As part of efforts to improve competitiveness, the DR's tracks were electrified during 1905 and new electric rolling stock was brought into use.

This involved carefully enlarging the tunnels under the Metropolitan Police's original headquarters at New Scotland Yard (now Norman Shaw Buildings).

[16] The station was completely rebuilt to incorporate new deep-level platforms for the Jubilee line when it was extended to the London Docklands in the 1990s.

The void, known as the station box, was the deepest ever excavation in central London and was carried out between thick reinforced concrete diaphragm walls stiffened and braced horizontally for stability.

The tubes were provided with a control system through which grout was injected into the ground to compensate for settlement detected from detailed measurements of the clock tower's position.

[17] The Jubilee line platforms were opened on 22 December 1999, although trains had been running through the station without stopping since 20 November 1999.