Until recently the sitter in this portrait was identified as Colonel William Northey, but recent comparison with a portrait by Gainsborough of Northey, painted circa 1760, shows that the traditional identification cannot be sustained, and that the real identity of the sitter is Richard Hopkins, and a portrait of Hopkins in the collection of Lord Boston confirms this. Graves and Cronin, loc. cit., list two portraits of a 'Mr. Hopkins'. The first sat in October 1755 and again in 1765, and a note in the artist's ledger records that the account was 'paid in full, September 27, 1766, Mr. Hopkins. #36 15s.' An additional note for this picture reads: 'Memo: "Mr. Hopkins' picture to be sent to Rev. Dr. Plumtree, Queen's College, Cambridge"'. A second and perhaps more likely portrait is the second listed: 'Mr. Hopkins, Junior', who sat in October 1755.

Richard Hopkins of Oving House, Buckinghamshire, was born circa 1728, the eldest son of Edward Hopkins, M.P., and his wife Anne Maria Chamberlain. Hopkins was a friend to August Henry, 3rd Duke of Grafton, who appointed him Clerk of the Board of the Green Cloth. He was a Lord of the Admiralty from 1782-3, and again 1784-91, and Lord of the Treasury 1791-8. He was Member of Parliament successively for Dartmouth (from 1766), Thetford (from 1780), Queensborough (from 1790) and Harwich (from 1796). He died unmarried on 19 March 1799 and his sister Anne, Mrs. William Northey, succeeded to the Hopkins estates; her third son assumed the additional surname and arms of Hopkins in May 1799, and this may be the reason for the confusion over the identifications of the sitter.

Hopkins is also recorded paying for portraits of Sir William Lee, the Duke of Grafton and Sir William Lowther.