DIMSDALE, Thomas (1712-1800), of The Priory, Hertford

Published in The History of Parliament: the House of Commons 1754-1790, ed. L. Namier, J. Brooke., 1964
Available from Boydell and Brewer



1780 - 1790

Family and Education

b. 29 May 1712, 4th s. of John Dimsdale, surgeon, of Theydon Garnon, Essex by Susan da. of Thomas Bowyer of Albury Hall, Herts.  educ. pupil to his father; St. Thomas' Hospital.  m. (1) July 1739, Mary (d. 4 Feb. 1744), da. of Nathaniel Brassey (q.v.) of Roxford, Herts., s.p.; (2) 17 June 1746, Anne (d. 1779), da. of John Iles, and ‘a relation of his first wife’,1 7s. 2da.; (3) 3 Nov. 1779, Elizabeth, da. of his cos. Joseph Dimsdale of Bishop's Stortford.  suc. to Herts. estates of his cos. Sir John Dimsdale on d. of his wid. after 1745.

Offices Held


The Dimsdales were Quakers, and Thomas's grandfather Robert Dimsdale, surgeon, accompanied William Penn on a visit to America in 1684. Thomas himself set up in practice in 1734 at Hertford; and was a surgeon in the army during the rebellion of 1745. The fortune of his second wife and the inheritance he received from Lady Dimsdale enabled him to retire from practice, but his family becoming numerous, he resumed it, taking his degree of M.D. in 1761 at King's College, Aberdeen. In 1766 he published a treatise on inoculation for smallpox, and in 1768 he inoculated the Empress Catherine and her son, for which he received ‘an annuity of £500, the rank of a baron of the Russian Empire ... £10,000 and £2,000 for travelling charges, miniature pictures of the Empress and her son, and the same title to his son ... The baron inoculated numbers of people at Petersburg and Moscow; and, resisting the Empress's invitation to reside as her physician in Russia, he and his son ... returned to England.’2 He next opened his own ‘inoculating house’ at Hertford. About the same time he entered banking; and although he himself retired from the firm in 1776, the business was continued by his sons, and further descendants.3

In 1780 Dimsdale stood for Hertford, and his own popularity, the Dimsdale-Brassey interest, and the Quaker vote made him top of the poll, above William Baker and defeating John Calvert, both strong local candidates. The English Chronicle wrote about him in 1781:

He is very much distinguished in his profession by the industrious and honest exercise of which he has acquired an independent fortune ... He owes his seat entirely to the good opinion entertained of him by his electors, amongst whom he is an old and favourite resident. Oratory is not one of his talents, but it is believed, however, that he will at least pronounce the decisive monosyllable with eloquence, with the genuine eloquence of sincerity, and vote upon every subject from the unbiassed influence of his principles and conviction.

About his one recorded speech (on the receipts tax, 12 June 1783), the reporter writes that he ‘spoke for some time, but in so low a tone, that we could not distinctly hear him’.4

As a Quaker Dimsdale naturally voted against the war, 12 Dec. 1781 and 22, 27 Feb. 1782, and, later on, for Shelburne's peace preliminaries, 18 Feb. 1783. But he was not in regular opposition to the North Government: he voted against the motion for removing them on 8 Mar. 1782, but for the ‘no confidence’ motion on the 15th. He voted against Fox's East India bill; belonged to the St. Alban's Tavern group which in January 1784 tried to bring about a coalition between Pitt and Fox; but after that must have supported Pitt, being classed as his supporter in Stockdale's list of 19 Mar. 1784. He was re-elected after a contest in April. In the new Parliament his only recorded vote was with Pitt over the Regency, 16 Dec. 1788. He did not stand in 1790, his son Nathaniel succeeding to his seat.

He died 30 Dec. 1800.

Ref Volumes: 1754-1790

Author: Sir Lewis Namier


  • 1. Gent. Mag. 1801, p. 669.
  • 2. Ibid.
  • 3. F. G. Hilton Price, London Bankers, 52-53.
  • 4. Debrett, x. 161