The back parlour was at the rear on the ground storey of the house.

This design was not executed at 8 Royal Terrace, and instead a design was installed for which there is no extant drawing. It made use of drops of calyx in the stiles, jugs in the capitals, and a frieze of anthemia, calyx and festoons. It survived to be photographed by the LCC in 1936, and was sold at auction in the same year.

This design makes use of the same frieze as that designed by Adam in 1766 for the dining room at Ugbrooke (Adam volume 22/170). The Ugbrooke design is inscribed in pencil with the words, 3d House / River front / Back Parlor, suggesting that Adam had considered reusing it in the back parlour of number 2 Royal Terrace, although the extant design for the chimneypiece for the back parlour at number 2 Royal Terrace (Adam volume 24/28) does not correspond with the Ugbrooke design.