Mann, who had inherited over £100,000 from his father, became a leading Kentish landowner in 1775, when his uncle, Sir Horatio Mann, 1st Bt., British envoy in Tuscany and friend of Horace Walpole, made over the family estates to him in return for an annuity. He joined Brooks’s in 1780, became an increasingly severe critic of North’s administration as the American war progressed, did not vote on Fox’s East India bill and belonged to the St. Albans tavern group of country gentlemen who tried to bring about a union between Pitt and Fox. He did not stand for Parliament in 1784 and was in Florence when his uncle died there, 6 Nov. 1786. He agreed to act as chargé d’affaires until a successor was appointed, on the assumption that he would receive a salary, but government made him only the ‘paltry, ignominious offer’ of £2 a day, which he indignantly refused. He was relieved after six months, complaining of the ministry’s ‘studied contempt’ for his services. His subsequent applications for compensation were ignored and in 1788 he had to return to Italy to deal with financial problems created, so he claimed, by the expenses incurred in maintaining his late uncle’s establishment in Florence.
Mann joined the Whig Club on 19 Jan. 1790 and at the general election later in the year defeated an administration candidate at Sandwich, where his estates gave him considerable influence and where, according to Oldfield, he was ‘much respected for his hospitality and convivial talents’.
Mann’s life, as Joshua Wilson recorded, was ‘dedicated to pleasure rather than to business’.
I shall attend it and probably remain in London for the first fortnight when may be expected the great press of business. To intermit a long tedious residence in London, I shall go to Bath for six weeks and then take a house in London.
Lincs. AO, Heron mss.
His ‘hereditary friend’ the gout (Elizabeth Cornwallis reported early in January 1801 that ‘He always has it about this time of the year’) no doubt made his attendance still more infrequent. He had periods of leave because of ill health in 1803 and 1807.
Mann again escaped a contest at Sandwich in 1806 when he joined forces with the Grenville ministry’s Admiralty candidate. He repeated the manoeuvre a year later with the Portland ministry’s man, but found the local strength of Admiral Peter Rainier too strong for him. Although he informed Lord Hawkesbury, 1 Nov. 1807, that ‘I will never fail to cultivate the interest I have in Sandwich’, his ill health and reduced circumstances put any further intervention beyond him.
Samuel Egerton Brydges recalled Mann as ‘a wild, fickle, rattling man, who made no impression’; and Farington wrote, 19 Oct. 1811: ‘In Kent there is no great controlling property. That possessed by Sir Horace Mann would have been the largest but by his extravagance he has reduced his income to not more than £4,000 a year.’
