 In 1794 Beaumont raised the 21st Light Dragoons and served as the regiment's colonel until 1802.He entered the British House of Commons in 1795 and sat for Northumberland first in the Parliament of Great Britain, then in Parliament of the United Kingdom until 1818.Beaumont married Diana Wentworth, daughter of Sir Thomas Wentworth, 5th Baronet, by whom he had three daughters and five sons, including