When Legge was restored to the Chancellorship for the third time in July 1757, Martin was the only person who had gone out of office in April who was not given a new job in the Pitt-Newcastle Coalition. Having failed to obtain an office in the King's service, Martin was compensated by being appointed Treasurer to the Princess Dowager of Wales Augusta of Saxe-Gotha (mother of the future King George III of the United Kingdom) in October 1757, an office he retained until 8 February 1772. In 1760 King George III succeeded to the throne and Martin was able in the following year to transfer his political loyalty from Legge (who was becoming less prominent in public life) to the King's favourite John Stuart, 3rd Earl of Bute.