New Government Offices (HM Treasury) and archway link with Foreign Office at east end of King Charles Street

New Government Offices (HM Treasury) and archway link with Foreign Office at east end of King Charles Street

Government offices built between 1898 and 1901 by John Brydon, completed with modifications in 1912 by the government architect Sir Henry Tanner. The building is constructed in Portland stone with leaded and slate roofs.

This is a massive, quadrangular English Baroque revival building that extends through to St James's Park. At its centre is a vast circular courtyard entered by triple archways from side streets, arranged on the same axis as the archways to the Foreign Office. The design echoes the Jones-Webb Whitehall Palace scheme.

The building rises four storeys, with a rusticated ground floor and mezzanine set above a basement. Two upper storeys are articulated by an engaged Corinthian column order, with angle pavilions featuring belvedere storeys topped by three-tier Baroque cupolas.

The Whitehall facade is symmetrical and seventeen windows wide, including one at each angle pavilion and a five-bay centrepiece with a tetrastyle pedimented portico. At its centre is a semicircular arched portal beneath the portico, flanked by columns and crowned with a pediment. The main second floor features recessed glazing bar sashes in pilastered frames with alternating pediments. The portico has coupled columns with a carved pediment set against a blind attic. Coupled pilasters to the angle pavilions are surmounted by belvedere attics containing inscribed, Vanbrughian Venetian windows with a coupled Ionic pilaster order. A tall entablature runs above the mezzanine with blind balustrades to the second floor windows. A deep main entablature has a modillion bracket cornice and balustraded parapets.

The Parliament Square and Great George Street front is thirty-three windows wide and contains angle pavilions with a recessed nine-window-wide centre topped by a tetrastyle portico over a triple archway flanked by cupola-pavilions. The coupled column portico above the triple archway has a pediment set against an attic with oculi in its flanking sections. The three-tier, Wren-inspired cupolas of the flanking pavilions have diagonally set rusticated columns to their main stages. The long ranges between the angle pavilions are not articulated by the Corinthian order on their upper floors but feature alternating pedimented second floor windows, two of which are Venetian windows with carved festoon and "linge" enrichments to the windows above. The Corinthian order reappears in the four-window west extension.

A four-window extension and lower quadrant return face the Park front. This elevation resembles the Whitehall facade but with three-storey quadrant corners in place of angle pavilions. These have engaged Ionic colonnades that echo Scott's adjoining Foreign Office.

At the east end of King Charles Street is a triple archway containing a passage-way link in its attic to the Foreign Office. The archway features engaged Doric columns and large-scale figure sculpture enrichment by J R Mountfield. A balustraded parapet to the basement area extends out to Storey's Gate, linking with a small stone kiosk and terminating in a large corniced pier crowned by an urn.

The main circular courtyard has an arcaded ground floor and an engaged Corinthian order above. The interior contains a large double branching grand staircase. The reinforced concrete basement at the Park end houses the "War Rooms" – Sir Winston Churchill's flat and office bunker during World War II.