Martin was based in the Downs under Admiral Edward Vernon in December 1745, and then succeeded Vernon in the command. The fleet had been based off the Downs to meet the threat of a French invasion to support a Jacobite rising. One such fleet had already been dispersed the previous year, and with the collapse of the threat Martin returned to his usual station, and commanded the main fleet until his retirement in July 1746 on health grounds. He was promoted to full admiral on 15 July 1747, and retired to Twickenham where he died on 17 September 1756. He had married Mary Atkins, of Twell, Gloucestershire on 16 August 1726, but the couple did not have any children.