The Treasury building was built to the designs of William Kent between 1733 and 1736. Dorset House, to the east of the Treasury, was formerly part of the Duke of Monmouth's lodgings in the old Palace of Whitehall. The lease was purchased by the Duke of Dorset in 1725 and was passed on to his successors until the Crown purchased the leasehold interest in 1808, and in 1810 the lodgings (and tennis court) were converted into offices for the Home Department and the India Board (SOL, XIV, p. 75). In 1817 the India Board moved out and the Commissariat Department took over occupation of the offices, and in the following year alterations were made to improve communication with the Treasury, costing £619 (King's Works, VI, p. 551).

Catalogued here are two survey drawings showing the Treasury as existing before 1818 and five drawings with designs for alterations to the staircase in the Treasury. Of these 'Design No 3' (drawings [6] and [7]) was chosen, and it is this configuration that is shown in the plans of the Treasury buildings reproduced in the Survey of London, Vol. XIV, plates 83 and 84. The staircase, still surviving, is described by Ptolemy Dean as 'very plain, with cantilevered stone and with simple iron balustrading' (P. Dean, op. cit., p. 235).

Literature:
M. H. Cox and P. Norman (eds), Survey of London: Vol. XVI: St. Margaret, Westminster, Part III , 1931; J. M. Crook and M. H. Port (eds), The History of the King's Works: Vol. VI: 1782-1851, 1973, pp. 549-51.

Tom Drysdale, January 2015