11, Downing Street SW1

No. 11 Downing Street is a Grade I listed terraced town house built in 1682 as part of Sir George Downing's new street. It now incorporates one house and part of another, with the remainder occupied by No. 10. The building underwent significant alterations around 1723 to 1735 and was refaced, along with No. 10, between 1766 and 1775 by Kenton Couse. Early 19th-century alterations were also made, and major reconstruction and restoration took place under Raymond Erith from 1960 to 1964.

The exterior features darkened brick with a stuccoed ground floor and minimal stone dressings, topped with a slate roof. The house has three storeys, a basement, and a dormered mansard, and is four windows wide. The doorway, located in the second bay from the right, has a recessed panelled door and fanlight set within a stone architrave, complete with shaped consoles and a moulded cornice. The windows are recessed glazing bar sashes beneath flat gauged arches, with stone plat bands between the storeys and a brick band below the parapet, which has coping. The property is also adorned with cast iron area railings that feature a lampholder overthrow.

Inside, despite the reconstruction, the house retains a fine front compartment staircase with carved bracket tread ends and three slender turned balusters per tread. The Drawing Room is a more restrained version of that at No. 10, featuring two elegant statuary marble chimneypieces positioned opposite each other. The Dining Room, designed by Sir John Soane in 1825-1826, has a ceiling design that relates to Soane's dining room at Lincoln's Inn Fields, featuring a shallow fluted tent-dome flanked by narrow rectangles that lead up to skylights. No. 11 serves as the official residence of the Chancellor of the Exchequer.