During the early 1780s, Payne had formed a friendship with the rakish heir to the throne,
George, Prince of Wales. After acting as companion to
Lord Northington on a Grand Tour of Europe in 1785, Payne returned to the service of the Prince as his private secretary and
Keeper of the Privy Seal. Payne also ran the Prince's household and lent money to
Lord Sandwich, who was obliged to obtain for Payne the parliamentary seat of
Huntingdon, which he held from 1787 to 1796. During this period he was appointed captain of
HMS Phoenix but never served at sea, drawing the pay whilst pursuing his other duties. Following the succession crisis of 1788 when
King George III was struck down by
porphyria, Payne was an active supporter of the Prince of Wales's regency. Payne corresponded closely with other supporters but also participated in the Prince's frequent and extravagant masques and entertainments. He also helped conspire in the Prince's
illegal marriage to
Maria Fitzherbert and was once rebuked by the
Duchess of Gordon in the terms "You little, insignificant, good-for-nothing, upstart, pert chattering puppy" after being overheard making insulting comments about the Queen,
Charlotte of Mecklenburg-Strelitz. ==French Revolutionary Wars==