16, 18, 20, 22 South St Andrew Street, Edinburgh

The Prudential Assurance Office, located at 1 and 2 St Andrew Square in Edinburgh, is a former insurance office designed by Alfred Waterhouse and Son between 1892 and 1895. This four-storey building features a mezzanine and attic, showcasing an Early Renaissance style on a corner site. It is constructed of polished red sandstone ashlar and includes an octagonal six-stage corner turret with polished granite facing at the ground level. The turret has an elaborate doorway and a three-light arcaded window above, with the turret's orientation changing at the fifth stage and topped with a spire and weathervane finial.

The ground and mezzanine levels are connected by an arcade, with each arch spanning two bays wide. The upper floors are organized in paired bays separated by pilasters, featuring architraved windows. The first and second floors have bipartite windows, while the third floor has tripartite windows with transoms. The wallhead dormers are pedimented and finished with finials, and there are carved panels between the windows on the first and second floors. A heavy dentilled cornice sits above the second floor, leading to a solid parapet.

On the north elevation facing St Andrews Square, the building has eight bays, with the two western bays slightly projecting and featuring a corniced door and window at ground level. The third-floor windows are set within an arcade adorned with carved tympani. There are three bipartite dormers on the six left bays, and the projecting bays are topped with a tiered Dutch gable. The ground level includes a basement area.

The east elevation on South Andrew Street also has eight bays, with arcading at the ground level now featuring modern glazing. The two northern bays are recessed and narrower, containing single windows, and there is a single light dormer above. The next two bays feature a tiered Dutch gable, while the remaining bays lack arcading on the third floor.

The building has timber sash and case plate glass windows, with ashlar coped skews, corniced ashlar stacks, and grey slate roofing.

The interior was gutted and rebuilt in 1993, except for the public bar on the ground floor, which was formerly the public office, and the rooms above facing St Andrews Square. The public bar is lined with glazed terracotta in the Prudential livery and features three bays with two central piers supporting lateral arches. Above is a foliate thistle frieze and a terracotta cornice at the first stage. The southern side has two arcaded windows with stained glass in the upper stages, a recess at the ground level to the west, and an upper stage to the east with an internal bow window to the left and a pedimented doorway to the right. The interior also features a consoled cornice and a geometric plaster ribbed ceiling.

Simple cast-iron railings enclose the basement area.