General Sir William Henry Sewell, (c.1786 – 13 March 1862) was a senior officer in the British Army.
Sewell was of unclear parentage, and according to some reports, was an illegitimate son of the Prince Regent (later George IV). He was raised however by Robert Sewell and his wife Sarah. He was educated at Westminster School and Eton College under the name of W.H. Robertson and joined the British Army in 1806 as an ensign in the 96th Foot under the name of William Henry Sewell. He then exchanged to the 16th Light Dragoons and rose through the ranks, via different regiments, to be Lieutenant-Colonel of the 6th Foot in 1817.
He was appointed aide-de-camp to General Beresford, going with him in 1808 to the Peninsular War. He was present with Sir John Moore's army at Corunna, Talavera, Busaco, Nivelle, Nive, Bayonne, Orthes, Toulouse and the sieges of Ciudad Rodrigo, Badajoz, as well as several other minor engagements.
After serving on Lord Beresford's staff in Maida and South America in 1807 he stayed on to command a Portuguese cavalry regiment from 1816 to 1818. Following his return from the Peninsula, he served in India from 1828 to 1854 successively as Deputy Quartermaster General in command at Bangalore, divisional commander at Madras and finally Commander-in-Chief of the Madras Army. He transferred from the 6th Foot to the 94th Foot in 1841 and was made Major-General in that regiment in 1846.
