4 Jan. 1814. He joined Marshal Bellegarde at Vincenza on 12 Jan., accompanied him in the occupation of Verona early in February, and was present on the 8th at the battle of Valeggio, where he greatly distinguished himself and was nearly captured by the French. On the 10th he was present at the action on the right bank of the Mincio. On 28 March he went to Bologna, where he met Lord William Bentinck and Murat, with whom he commenced negotiations. The abdication of Buonaparte put an end to his mission, and in June he left Italy for Paris.
On 10 Jan. 1816 Wilson was instrumental, in conjunction with Michael Bruce and Captain John Hely-Hutchinson (afterwards third Earl of Donoughmore), in the escape from Paris of Count Lavalette, who, having been condemned to death, had escaped from prison by changing dress with his wife. Wilson passed the barriers in a cabriolet with Lavalette disguised as a British Officer, and conveyed him safely to Mons. He sent a narrative of the adventure to Earl Grey (reprinted in Gent. Mag. 1816), which was intercepted. He was arrested in Paris on 13 Jan. The three Englishmen were tried in Paris on 2 April and sentenced on the 24th to three months' imprisonment (see Annual Register, 1816). On 10 May a general order was issued by the Duke of York, commander-in-chief, expressing the prince regent's high displeasure at the conduct of Wilson and Hutchinson.
In 1817 Wilson published ‘A Sketch of the Military and Political Power of Russia,’ which went through several editions, and was severely attacked by the ‘Quarterly Review’ (vol. xix., September 1818). In 1818 Wilson was returned as member of parliament for Southwark, defeating Charles Barclay, the brewer, and on this occasion he replied to the attack of the ‘Quarterly Review’ in ‘A Letter to his Constituents in Refutation of a Charge for despatching a False Report of a Victory to the Commander-in-chief of the British Army in the Peninsula in 1809.’ In 1820 he was again returned for Southwark, defeating Sir Thomas Turton.
Queen Caroline (1768–1821) [q. v.], who had been friendly to Wilson and to whom his eldest son was equerry, died on 7 Aug. 1821. Wilson attended the funeral on the 14th, when an encounter took place between the household cavalry and the mob at Cumberland Gate, Hyde Park. Shots were fired, and Wilson interposed to prevent bloodshed. He was peremptorily dismissed from the army on 15 Sept. without any reason being assigned, or any opportunity of explanation afforded. Having purchased all but his first commission, he lost a large sum of money, and a subscription was raised to compensate him for the loss. On 13 Feb. 1822 in his place in parliament Wilson moved for papers, and in a long and able speech (see Hansard) vindicated his action, and called in question the prerogative of the crown to dismiss any officer without cause. The government, confining themselves to the questions of prerogative, easily defeated the motion. In 1823 Wilson went to Spain to take part in the war first in Galicia and then at Cadiz. He was again returned to parliament for Southwark in 1826, when the poll lasted six days, and he defeated Edward Polhill. He made a speech in the House of Commons on 12 Dec. on the policy of aiding Portugal when invaded by Spain, which was published separately. He was an active politician, and took a prominent part in the formation of the Canning ministry (see Wilson, Canning's Administration: Narrative of Formation, with Correspondence, &c., 1827, ed. Herbert Randolph, 1872, 8vo). He was again returned to parliament for Southwark in 1830. On the accession of William IV Wilson was reinstated in the army with the rank of lieutenant-general, to date from 27 May 1825 (London Gazette, 22 July 1830). The Reform Bill was introduced in the House of Commons on 1 March 1831. Wilson regarded it as ‘the initiatory measure of a republican form of government,’ and in consequence, in spite of great pressure, refused to vote with the government and resigned his seat, losing for a time the colonelcy of a regiment and all opportunities of useful employment.
On 29 Dec. 1835 Wilson was appointed colonel of his old regiment, the 15th hussars. On 23 Nov. 1841 he was promoted to be general, and in 1842 he was appointed governor and commander-in-chief at Gibraltar. He had only recently returned home when he died suddenly on 9 May 1849 at Marshall Thompson's hotel, Oxford Street, London. He was buried on 15 May beside his wife in the north aisle near the western entrance of Westminster Abbey, and a fine memorial brass, next to the grave of John Hunter, marks the vault (for will cf. Chester, Westminster Abbey Register, p. 513).
Wilson married Jemima (1777–1823), daughter of Colonel William Belford of Harbledown, Kent, eldest son of General William Belford [q. v.] of the royal artillery. She was coheiress with her sister, Mrs. Christopher Carleton, of their uncle, Sir Adam Williamson [q. v.] Both Wilson
