11 Westgate Street

11 Westgate Street is a former shop and dwelling, now used as offices, dating from the early 19th century. It underwent a conversion and extension around 1875 to accommodate a gentlemen's club known as The Gloucester Club. The east wall, which borders the pedestrian entry to Mercer's Passage, features a section of medieval stone rubble wall that is believed to include reused Roman masonry. The building has seen 20th-century alterations, mainly to the ground floor, and there have been extensions at the rear. The original shopfront was replaced, and further interior changes were made in the early 21st century.

The building is constructed of brick with a stuccoed front and has a slate roof. It stands four storeys high and includes a cellar. The main façade is two bays wide above the ground floor, which has a glazed and timber-framed shopfront. There is a moulded band at the second-floor level, a plain band at the third-floor level, and a moulded cornice with a blocking course at the top. The upper floors feature plain sash windows set in openings framed by plain, slightly raised architraves, with roundels indented at each upper angle and projecting stone sills. The sills of the second and third-floor windows are supported by small, moulded end brackets.

Inside, the ground floor was refitted in 2018. Behind the shop, there is a stairwell with an early 19th-century dog-leg staircase that includes stick balusters and a ramped handrail. On the first floor, two rooms were combined around 1875 to create a large reception room for the Gloucester Club, which is elaborately decorated in a French 18th-century style, featuring moulded plaster panels on the walls and ceilings, moulded marble chimney pieces, and decorative joinery. Some early 19th-century joinery can also be found in other rooms.