Cotton served in Flanders in 1793-4 and at the Cape and in India from 1796 until the death of his elder brother brought him home in 1800. At the general election of 1806 he was returned for Newark by his brother-in-law, the 4th Duke of Newcastle. In March and April 1807 he was granted periods of leave because of the illness of his first wife,
It was noted in 1808 that Cotton ‘supports the present cabinet’,
Wellington recommended him for a red ribbon, which he duly received, but Cotton, who came home late in 1812, wanted a peerage, which his father had once declined. All the pressure exerted on ministers by Newcastle on his behalf was of no avail, but he was prevailed on to return to the theatre of war and on 11 Mar. 1813 was excused service on an election committee on this account.
