Major-General Sir William Ponsonby MP (1772–1815)

Ponsonby, a member of an Irish aristocratic family, was a long-serving Guards officer. He won a seat in the Commons as a supporter of the Whig opposition, which was led by his uncle George Ponsonby, but he was mostly away on military service.

Ponsonby commanded the Union Cavalry Brigade – made up of English, Scottish and Irish regiments – at Waterloo, where he was killed in action after a charge in which his horse got stuck in the mud. In his Waterloo Dispatch, Wellington 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.' Along with Thomas Picton, Ponsonby was one of two MPs killed during the battle.