In October 1761 he chose to stay in government and accepted the new role of Leader of the Commons causing a rift with his brother-in-law and political ally William Pitt who had resigned.

He allied himself with his brother Richard and with William Pitt (who became their brother-in-law in 1754) in forcing Pelham to give them promotion by rebelling against his authority and obstructing business.

Along with Pitt and several other colleagues he was dismissed in 1755 after speaking and voting against the government on a debate about a recent subsidy treaty with Russia which they believed was unnecessarily costly, and would drag Britain into Continental European disputes.

Grenville and Pitt both championed the formation of a British militia to provide additional security rather than the deployment of Hessian mercenaries favoured by the government.

[5] As the military situation deteriorated following the loss of Minorca, the government grew increasingly weak until it was forced to resign in Autumn 1756.

Grenville was returned to his position as Treasurer of the Navy, which was a great disappointment as he had been expecting to receive the more prestigious and lucrative post of Paymaster of the Forces.

[6] This added to what Grenville regarded as a series of earlier slights in which Pitt and others had passed him over for positions in favour of men he considered no more talented than he was.

[7] In 1758, as Treasurer of the Navy, he introduced and carried a bill which established a fairer system of paying the wages of seamen and supporting their families while they were at sea which was praised for its humanity if not for its effectiveness.

However his seven-year-old son died after a long illness and Grenville remained by his side at their country house in Wotton and rarely came to London.

[9] In 1761, when Pitt resigned upon the question of the war with Spain, and subsequently functioned as Leader of the House of Commons in the administration of Lord Bute.

[10] In May 1762, Grenville was appointed Northern Secretary, where he took an increasingly hard line in the negotiations with France and Spain designed to bring the Seven Years' War to a close.

[11] Grenville demanded much greater compensation in exchange for the return of British conquests, while Bute favored a more generous position which eventually formed the basis of the Treaty of Paris.

Bute's position grew increasingly untenable as he was extremely unpopular, which led to him offering his resignation to George III on several occasions.

When Grenville was asked about becoming the new prime minister, he agreed only on the condition that Bute would not take an active part in politics and be barred from voicing policies for the government.

In 1763, it came to be one of Grenville's first acts to prosecute Wilkes for publishing in The North Briton newspaper an article deriding King George III's speech made on 23 April 1763.

Although, initially, prominent measures of his government included the prosecution of John Wilkes, focus shifted from arresting radicals to paying off the national debt.

The passing of the tax measures in America had proved to be a disaster and would lead to the first symptoms of alienation between American colonies and Great Britain.

Enacted because of a request by Major General Thomas Gage, commander-in-chief in North America, to give better housing for his troops stationed in the colonies.

But overall the British relations, after negotiating, with the French and the Spanish, remained hostile and suspicious of its enemies and that wariness concluded the entirety of Grenville's policy.

[3] After a period of active opposition to the Chatham Ministry led by Pitt between 1766 and 1768, Grenville became an elder statesman during his last few years – seeking to avoid becoming associated with any faction or party in the House of Commons.

Grenville prosecuted John Wilkes and the printers and authors for treason and sedition for publishing a bitter editorial about King George III's recent speech in "The North Briton" a weekly periodical.

[20] In 1770 Grenville steered a bill concerning the results of contested elections, a major issue in the eighteenth century, into law – despite strong opposition from the government.

In the long-term, the Grenvillites were revived by William Pitt the Younger who served as prime minister from 1783 and dominated British politics until his death in 1806.

Subsequent analysis of these specimens published by the Royal College of Surgeons of England suggests that George Grenville was affected by Multiple myeloma at the time of his death.

Its record is a prominent orogenic belt which spans a significant portion of the North American continent, from Labrador to Mexico, and extends to Scotland.

)[15] At the time of his death in 1770, he was the heir presumptive to the Earldom of Temple held by his elder brother Richard (who had succeeded their mother in that title in 1752, but had no sons).