Offley was a man of fashion, prominent in gaming circles, and a friend of Lord Lincoln, Newcastle’s nephew and heir. Politically he was a Pelhamite, and in 1754 was returned for the Treasury borough of Orford. In 1756 he was appointed to the sinecure of surveyor of the King’s private roads, which seems to have been worth about £500 p.a.; to which was annexed an additional salary of £318 p.a., and in October 1756 a further £200.
In October 1762 Offley was approached by Henry Fox about his attitude to Bute’s Administration. ‘Mr. Offley’s answer ... ’, wrote Newcastle to James Peachey,
Though his character was never rated very high and he was irregular in attending the House, he was one of the very few who remained with Newcastle to the end. He was a member of Wildman’s Club (but he had disapproved of the idea of starting it),
At the general election of 1768 Offley was returned as the Pelham candidate at East Retford, supported by both Newcastle and Lincoln. ‘Mr. Offley is no party man’, wrote Newcastle to Mansfield on 7 Dec. 1767, ‘and has no particular attachment to any. He has constantly acted honourably with his friends, and will certainly continue to do so.’ He was classed by Robinson as ‘contra, present’ on the royal marriage bill, March and again as ‘contra’ in September 1774. In 1772 he was willing to retire from Parliament when a seat was required for Lord Lincoln (son of the 2nd Duke of Newcastle);
Offley died 3 Apr. 1784, aged 66.
