Of an Irish Roman Catholic family, Warren entered the navy under the care of his uncle Admiral Matthew Aylmer, becoming a Protestant.
Commodore Warren has behaved, in the whole affair, so much like an officer who has nothing so much at heart as his Majesty’s service, and so much to the satisfaction of us who employed him, as well as to that of all the officers who had the pleasure to serve under him, and has kept up so good an agreement, by his prudent conduct, with the officers that commanded the land forces, that I should think myself highly deficient in my duty to the King was I not to represent how much I thought it was for his Majesty’s service to reward so much merit in a conspicuous manner.
Bedford Corresp. i. 28-29.
Refused a baronetcy on the ground he had no heir, he was made a rear-admiral. In that year he took several more valuable prizes from the French. In the spring of 1747 he was second-in-command at the victory off Cape Finisterre under Anson, whom he succeeded as commander of the Channel fleet. Suffering from a ‘scorbutic disorder’,
Having failed to obtain the governorships of New York and of New Jersey 1745-6, Warren then expressed his intention ‘to get into Parliament and perhaps venture to open my mouth with more temper though less eloquence than our friend Mr. Vernon.’ He was returned for Westminster on the interest of the Duke of Bedford, who provided him with the necessary property qualification.
I beg you will assure his Grace the Duke of Bedford and yourself that I shall ever, upon all occasions adhere with a most firm and an unchangeable attachment to his Grace’s and your interest and service.
9 Aug. 1747, Add. 15957, f. 208.
Pelham put him forward in 1748, but the King turned him down. In March 1749 he was one of the high naval officers who ‘vehemently opposed’ the navy bill.
