Manners was predestined for a seat for Leicestershire on the family interest and in 1798 appeared at the county meeting in company with his locum tenens Sir Edmund Cradock Hartopp, but his path to it was not smooth. As a young cavalry officer he was trampled upon by part of his regiment after being thrown from his horse at the review at Ashford Common in 1801 and considered fortunate to escape with his life. In 1802, still not of age, he was put up by his brother on the family interest at Scarborough and was returned after a contest. In the House he followed the family line. A protégé, through his mother, of the Prince of Wales, he voted for inquiry into the Prince’s financial claims, 4 Mar. 1803, but did not otherwise oppose Addington. He was listed a Pittite in September 1804 and July 1805 and shared his brother’s reservations about the Grenville ministry.
At the general election of 1806, after some difficulty in nudging out Cradock Hartopp, Manners came in for Leicestershire. He was reluctant to do so. Farington reported that the duke had obtained John Mansfield the receiver-generalship of the county worth £3,000 a year on condition that his brother received half of it.
The contest for Leicestershire in 1818 was not directed against Manners, although there were ominous rumblings about ‘patrician influence’. In the ensuing Parliament he voted with ministers against Tierney’s censure motion and for the foreign enlistment bill, 18 May and 10 June 1819. No speech of his in debate is known. Indeed, he informed the duke in an undated letter, probably in March 1829: ‘I always told you I was not fit to represent the county of Leicestershire. You say in your letter you wish I had courage to speak, but you must first give me the ability.’ He died 15 Nov. 1835, ‘deservedly beloved by his family and his friends’.
