The history of Pembroke House is set out by Steven Brindle in 'Pembroke House, Whitehall', The Georgian Group Journal, vol. VIII, 1998, pp. 88-113. It would appear that in 1723 alternative proposals for the house were under consideration. Campbell's proposal won the day, since he published a variant of his initial design, 1, in volume III of Vitruvius Britannicus in the following year (pl. 48), giving the date 1724, and stating that the gallery of the building at attic level 'is most magnificently finished, and gives one of the best Prospects of the Thames'. This was on the rear, or east elevation, of the building, facing the river. His published design shows this attic storey to have a three-light Venetian window, above a three-arched opening at first-floor level. A topographical view of 1737 shows that these two levels of opening were built, although not beneath the straight parapet implied by Campbell's front elevation (Brindle, op. cit., fig. 7); instead, the rear elevation is in three separately roofed bays, each with a pyramidal roof. Dickinson's rejected design, 3, is a developed version of his scheme on the right-hand side of 2. In Dickinson's two alternative proposals at 2 and 3 a large octagonal cupola s