Thompson was the heir of Capt. Edward Thompson, RN, of Epsom, who launched him on his naval career and died in 1786. By one account, Edward Thompson was his father, and his mother Sarah née Boulden of Kent (he was born at Barham); by another he was the son of an impecunious man named Boulden by his wife Sarah, daughter of Richard Thompson, and Edward Thompson’s sister. As he was certainly known in his youth as Boulden and referred to in Edward Thompson’s will as Boulden ‘alias Thompson’, without their relationship being specified, he either assumed the name of Thompson as a compliment to his uncle or because Edward Thompson was in fact his father.
Thompson’s naval career was varied and distinguished, earning him professional esteem, a knighthood and a pension of £200 p.a. in 1799. The loss of a leg on active service in 1801 raised his pension to £500. Even so, in 1804 Addington, the outgoing prime minister, informed St. Vincent at the Admiralty that some provision must be made for Thompson’s family, ‘for it will not be in his power to make much saving out of his income with the most rigid economy’. His pension was increased to £700 under the Grenville ministry, which appointed him comptroller of the navy with a baronetcy.
Thompson continued in the Treasury line in the Parliament of 1812, to which he was returned unopposed. He had opposed Catholic relief on 22 June 1812 and did so throughout 1813, as also on 21 May 1816. He voted for Christian missions to India, 1 July 1813. He was in the government majorities on the civil list, 14 Apr., 8 May 1815 and 24 May 1816, and in their minority on the Duke of Cumberland’s establishment, 3 July 1815. He also voted with them on the army estimates, 6 and 8 Mar. 1816. He had then just exchanged the comptrollership of the navy for the treasurership of Greenwich Hospital. On 11 Mar. Charles Williams Wynn suggested to the House that he ought to have vacated his seat on taking up a remunerative office, (under 6 Anne c.7), and on 27 Mar. moved for a new writ for Rochester. After some debate as to precedents, none more recent than 1736, the matter was referred to a select committee. When on 1 May Williams Wynn moved that Thompson’s appointment was not, as the committee alleged, a commission in the army or navy, the previous question was carried against it by 65 votes to 47; but on 6 June, John Calcraft presented a petition from Rochester calling for Thompson to submit to re-election and on 12 June carried the point by 69 votes to 68.
