Joining the opposition benches, Barrington took his seat in 1741 for Walpole's dismissal, voting down a bill for manning the fleet on the grounds it would increase the 'Court Whigs' influence on the coast.

Barrington was among the opposition peers consulted for a new ministry in 1744 between the Cobhamites and the incumbent Pelhamites, removing Carteret, now earl Granville, and his Tory friends from office.

Barrington's subsequent Paper on the Plague helped to establish a House of Recovery for the Sick at Gray's Inn, which was extended to the dying and suffering in London.

The cabinet insisted the rock must be held as a strategic naval base; Barrington's experience told him this, switching the Governor's detachment, a battalion onto Byng's flagship.

[9] In the event the garrison could not spare the men: facing the threat of an attack by the Toulon fleet, Barrington was clear in a subsequent letter that Gibraltar must not be left undefended.

Cumberland was disgusted at the loss of Port Mahon, its naval base, and the shame brought upon the military's discipline and reputation, adding to the Secretary's political problems; Barrington consequently clung to Newcastle's patronage at least in part for self-preservation.

Modern historians have laid the blame at barrington's door for the confusion that ensued from the contradictory orders; but much of the contention has derived from his belated conversion to Toryism, and embracing of a Pittite bluewater policy with all its attenuated risks.

[10] Barrington remained a staunch friend and ally of Newcastle throughout, always grateful for the confidence, but never afraid to differ from the duke "to whom I owe more compliance than to any man living, because he is the only subject, to whom i have a real obligation.

I must do his Grace the justice...."[11] The previous October he had advised Field Marshall Ligioner, by now a Viscount, that his brother was over-promoted "I again deprecate Colonel Barrington being so near the command; and i entreat of your Lordship to recommend some other Major-General to His Majesty, in case Mr Boscawen should be excused.

"[12] In the light of his compassion, the story of Colonel Monro's Arabian horse seemed typical of the man's discreet delicacy, nursing his gifted steed back to health, but putting its ownership into trust.

Barrington was always careful to avoid accusations of taking sweeteners or inducements for corrupt practices; sufficiently astute to defer on matters of ethical credibility to others.

In 1762 the Tory Prime Minister proposed Barrington Treasurer of the Navy, which he accepted, but remained close to the duke, who declined to oppose the new ministry.

[17] Bute suggested enlarging the government with a Foxite Coalition; but Barrington, who long been a friend of Charles James Fox felt "a coolness between us".

[19][a] At a meeting at Newcastle House, London, on 11 November the duke pressed Barrington to end his support, knowing the ministry would fall, which it did in April 1763.

On 17 July 1765 Barrington returned to London to seek his former position of secretary at war from the King whom he told: "That a man like me, solely attached to himself, must not expect many Court friends",[20] at St James's Palace as department GHQ, at once abandoned by General Ligonier, who preferred the esprit de corps of Knightsbridge.

On 26 July, Barrington, the prospect of joining a Tory Chatham ministry looming over the horizon, played his royal hand again to stay in government.

[23] Disliked by the Commander-in-chief Lord Ligonier, eyed warily from the Guards barracks at Knightsbridge, Barrington immediately had to deal with a number of crises: The Weavers and Corn Riots prompted the Life Guards out onto the streets, The present riotous assemblings on account of high price of corn made it necessary for the Magistrates to call in a military force to their assistance,wrote mr Secretary.

[25] This hard line approach to complex legal problems characterised the ministry, the non-importation embargo for instance begun by the Americans in 1768/9 was bankrupting the East India Company; the dumping of China tea just one expression of the violence to follow.

[26] So when John Wilkes petitioned to be allowed to take his seat in the Commons, Barrington and the Paymaster of the Forces, Richard Rigby led the cabinet in throwing him out.

[29] Even Barrington was not altogether convinced of Burgoyne's abilities to resist corruption, and the practice of commission purchases, an issue he helped straighten with the firm.

...after a series of favours of which the army does not furnish a precedent, and to which with all his amiable and valuable qualities as a man he had not the least claim as a soldier...Has Lieutenant-Colonel Burgoyne a right to every douceur, which General Elliot may expect?

In 1759 Burgoyne had threatened him; Barrington responded "with the House of Commons, in case i am, what you call partial against you...the least courtly letter that was ever written to a Secretary at War."

Ending the practice of in commendam holding every second corps in reserve because it was ruinous to finances exemplified his public policy credentials of saving graces, but critics thought it left England dangerously exposed to invasion from the continent.

Burgoyne's catastrophic defeat was the catalyst: finally, after a protracted and agonising wait, he could no longer hold his own counsel "or oppose them, without affecting my honour and duty".

Lord North's defeat however ushered in the whiggish friends of America to conclude the Paris Treaty, forcing Barrington to resign in April.