Wentworth may have been born in Barbados. He moved to Portsmouth, New Hampshire in the 1750s, and won the patronage of the governor Benning Wentworth. He settled in Surinam in about 1760 where he married a widow, and on her death inherited a sugar plantation. In 1764 he hired Edward Bancroft to survey and improve the Surinam plantation and in 1766 left for London. He established himself as a stockbroker or speculator in London and Paris. John Wentworth the next governor of New Hampshire appointed him as a member of the New Hampshire council and also as the province's agent to the Parliament of Great Britain despite the two offices needing to be on opposite sides of the Atlantic.
Intelligence activities
Wentworth decided that the British crown offered better opportunities than the Americans. He started supplying information to the British secret service in 1772. When the American war began, Sir William Eden, head of the British secret service, granted Wentworth a pension of five hundred pounds a year for his services. Wentworth was to spy on the American delegation to the French court when Silas Deane was sent to Paris in 1776. Deane and Benjamin Franklin were both old friends of Wentworth and he could easily make the necessary contacts. Wentworth's friend Edward Bancroft joined the American mission in Paris in 1776 and. Wentworth recruited him to spy for the British government in December 1776. In 1777 Pierre Beaumarchais wrote to Vergennes that Wentworth spoke French "like you and better than I do: he is one of the cleverest men in England". In 1778 Wentworth was in discussions with Franklin on peace terms but the effect of this was to help drive the French into alliance with the Americans. Wentworth was seeking a baronetcy, a place at the Treasury Board, and a seat in Parliament and wanted a British victory to save his New Hampshire estates. He built up and controlled a spy network and provided military intelligence to the British government on the basis of the reports he gathered. He often went in disguise to mainland Europe but in time the French police recognized him and he had to stay in London. Lord North considered him "the most important and truest informer" although George III had little confidence in his reports and disliked his speculative activities.
