In 1746 Grenville obtained the governorship of Barbados through the influence of his brother George. He returned to England in 1755 and resigned the following year. On 18 Nov. 1756 Dodington noted in his diary (p. 391):
Mr. Tucker [M.P. for Weymouth and Melcombe Regis] had agreed with Mr. George Grenville to be paymaster of the marines and for Governor Grenville to be chosen in his place. The King sent to Fox to know if he could prevent it, and if he thought I would interpose. Mr. Fox said he supposed, if his Majesty commanded me, I would. The King ordered Fox to speak to me—he did, and I stopped it. This is the first step towards turning out Lord Temple.
In February 1759 George Grenville arranged that Walter Waring, M.P. for Bishop’s Castle and patron of the borough, should resign in Henry’s favour: ‘Mr. Waring’s interest and Mr. Pitt’s popularity united seemed to me invincible there’,
In 1768 Grenville was returned unopposed at Buckingham on Temple’s interest. In Parliament he now voted consistently with Opposition. There is no record of his having spoken in the House. In April 1774 Temple requested Grenville to resign his seat and proposed to return their nephew George Grenville jnr. in his place as soon as he came of age in June. But on young George’s protesting that he did not wish to supplant his uncle before the general election and that ‘it was never understood that he held it in trust for me’,
He died 22 Apr. 1784.
