Simson, who applied for an East India Company writership in 1783, went out to Bombay. On his return, he became a partner in the London East India house of Bruce, De Ponthieu, Bazett & Co. and in the London bank of Were, Bruce, Reed, Simson and Taylor, which started at St. Bartholomew’s Lane in 1802. He invested in East India Company stock. Three of his partners, Patrick Crauford Bruce, John De Ponthieu and Henry Fawcett entered Parliament at the same time as himself.
Simson was an inconspicuous or cautious Member. No speech of his is known. He is not known to have joined any minority until 21 Feb. 1809, when he did so on the convention of Cintra. He joined opposition on Lord Chatham’s conduct, 23 Feb. 1810, and they tried to ‘frighten’ him, by constituency pressure, into voting with them on the Scheldt inquiry, 30 Mar., but he voted with government. The Whigs listed him ‘Government’. He was in the minority for the discharge of John Gale Jones, 16 Apr., but opposed parliamentary reform, 21 May 1810. He sided with ministers on the Regency, 1 Jan. 1811, but no further votes are known in that Parliament. He was perhaps preoccupied with the reorganization of his business firm (styled Bruce, Simson, Freen and Mackenzie from 1812) and with the purchase of Sunninghill in Berkshire from James Sibbald.
When Simson was listed a ministerial supporter in 1812, Canning remarked, ‘If at all, I believe him to incline to me—but to me and government rather’.
Simson did not seek re-election in 1818. His banking partnership appears to have folded up, though it re-emerged in 1819 as Bruce, Simson & Co. of Austin Friars. Perhaps Simson’s son was the partner in question. It crashed in 1825. He had meanwhile retreated to his native Fife. In 1820, described as a former London banker, living at Woodmill, he showed an interest in contesting a Scottish burghs seat as a friend of government. In 1831 his heir contested Maidstone, unsuccessfully. He died at Pitcorthie House in Fife, 7 July 1848, aged 81. According to family tradition, he twice refused a baronetcy.
