Anglesey's order was that the Royals and Inniskillings should charge and the Greys should support, but the latter came up into front line before the other regiments were half way down the slope. The French columns broke up, and two thousand prisoners were taken. Sir De Lacy Evans, who was acting as extra A.D.C. to Ponsonby, says: 'The enemy fled as a flock of sheep across the valley, quite at the mercy of the dragoons. In fact our men were out of hand. The general of the brigade, his staff, and every officer within hearing exerted themselves to the utmost to re-form the men; but the helplessness of the enemy offered too great a temptation to the dragoons, and our efforts were abortive.' They mounted the ridge on which the French artillery were drawn up, and, meeting two batteries which had moved forward, sabred the gunners and overturned the guns. The household cavalry brigade, which had charged at the same time on the right, became to some extent intermixed with the Union brigade. Napoleon, seeing the situation, sent two regiments of cuirassiers to fall on the front and flank of the disordered cavalry, and they were joined by a regiment of Poplish lancers. 'Every one,' says Evans, 'saw what must happen. Those whose horses were best, or least blown, got away. Some attempted to escape back to our position by going round the left of the French lancers. Sir William Ponsonby was of that number' (Waterloo Letters. p. 61). He might have escaped if he had been better mounted, but the groom with his chestnut charger could not be found at the moment of the charge, and he was riding a small bay hack which soon stuck fast in the heavy ground. Seeing he must be overtaken, he was handing over his watch and a miniature to his brigade-major to deliver to his family, when the French lancers came up and killed them both on the spot. He was buried at Kensington, in the vault of the Molesworth family, and a national monument was erected to him in St. Paul's. The Duke of Wellington, in his report of the battle, expressed his 'grief for the fate of an officer who had already rendered very brilliant and important services, and was an ornament to his profession.'
Ponsonby married, 20 Jan. 1807 the Hon. Georgiana Fitzroy, sixth daughter of the first daughter of the first Lord Southampton. and he left one son. William, who succeeded his uncle John Ponsonby as third Baron Ponsonby—a title now extinct—and four daughters.
[Gent. Mag. 1815; Burke's Extinct Peerages; Records of the 5th Dragoon Guards; Siborne's Waterloo Papers; Statement of Service in Public Records Office.]
PONSONBY, WILLIAM BRABAZON, first Baron Ponsonby (1744–1806), born on 15 Sept. 1744, was the eldest son of the Right Hon. John Ponsonby [q. v.], speaker of the Irish House of Commons, by his wife, Lady Elizabeth Cavendish, second daughter of William, third duke of Devonshire. George Ponsonby [q. v.], lord chancellor of Ireland, was his brother. He was returned in 1764 to the Irish House of Commons for Cork city, which he continued to represent until the dissolution in 1776. He represented Bandon Bridge from 1776 to 1783. At the general election in 1783 he was returned both for Newtown and Kilkenny county, but elected to sit for Kilkenny, and continued to represent that county until his elevation to the peerage. He voted against Flood's Parliamentary Reform Bill on 20 Nov. 1783 (Life and Times of Henry Grattan iii. 150-4 n.), and in July 1784 was appointed joint postmaster-general of Ireland and sworn a member of the Irish privy council. Having declared his opinion that the house ought 'to invest the Prince of Wales as regent with all the authority of the crown fully and unlimitedly' (Parl. Register, or History of the Proceedings and Debates in the House of Commons of Ireland, ix. 22), he was selected as one of the bearers of the address to the prince, which the lord lieutenant refused to transmit. He joined those who opposed the Marquis of Buckingham's policy in signing the round-robin agreement of 27 Feb. 1789 (Barrington, Historic Memoirs of Ireland, 1833, vol. ii. opp. p. 377), and was shortly afterwards removed from the office of postmaster-general. He was elected an original member of the whig club founded in Dublin on 26 June 1789. On 4 March 1794 he brought forward a parliamentary reform bill, which was substantially the same as the bill which he had introduced in the previous year, its principal features being the extension of the right of voting in the boroughs, and the addition of a third member to each of the counties and to the cities of Dublin and Cork (Parl. Reg. &c., xiv. 62 8). It was warmly supported by Grattan, but was rejected by the house by a majority of ninety-eight votes, Ponsonby appears to have been recommended by Fitzwilliam for the post of principal secretary of state in 1795 (Lecky, History of England, vii. 57). In May 1797 he brought forward a series of resolutions in favour of reform, but was defeated by 117 votes to 30 (ib, vii. 324-8). He voted against the union in 1799 and in 1800 (Barrington, Historic Memoirs of Ireland, ii. 374). On 16 March 1801 he took part in the debate on the Irish Martial