Thynne’s career in the Commons was that of a dependant of his elder brother, Thomas, 3rd Viscount Weymouth. Before he had come of age there was talk of his standing for Wiltshire where the Thynne estates mostly lay. ‘I hear there have been lately some public meetings’, wrote John Bull to Shelburne, 30 Oct. 1756, ‘where success has been drank to Mr. Thynne, Lord Weymouth’s brother, as one of our intended shire knights.’
In 1761 Thynne was returned for the family borough of Weobley. When Weymouth agreed to support Bute’s Administration he asked for a place for his brother. ‘Have you allotted Mr. Thynne to any particular employment?’, wrote Fox to Bute, 29 Oct. 1762; and Shelburne, 19 Nov.: ‘Lord Weymouth will not accept the groom’s place for his brother upon any account, made up or in any shape whatever.’
He lost it when the Grenville Administration was dismissed in July 1765. As a member of the Bedford group he voted against the repeal of the Stamp Act; and Bedford, when negotiating with Chatham in December 1766, included Thynne among those followers who had to be provided for. When the Bedfords joined Administration in 1768 Thynne was made master of the Household (£518 p.a.).
Weymouth, now secretary of state, tried to get him a more lucrative office, and it seems that in October 1769 he was promised the Madrid embassy. But on 1 Dec. Charles Lloyd wrote to Grenville:
Lord Rochford ... has seen Lord Weymouth this morning, [Rochford wrote to the King, 11 Dec. 1770] ... he suggested that if Lord Sandwich was made secretary of state for the northern department, the Post Office if given to Mr. Thynne would be vacant, and such an employment given to his brother would be a convincing proof to the world that he Lord Weymouth had not quarrelled with Administration. At the same time he would bring into his brother’s borough a determined friend to Government.
Fortescue, ii. 63, 140, 183.
The Post Office, not tenable with a seat in the Commons, was worth nearly £3,000 p.a. in salary and allowances. Thynne left most of the work to the secretary, Anthony Todd, from whom he also borrowed money.
Thynne died 17 June 1826.
