English diplomat and financial administrator who helped precipitate two wars with the Dutch and who instituted major reforms in public finance. Downing Street, London, where the residence of the British prime minister is located, is named for him.

The son of a Puritan lawyer, Downing was one of the first graduates of Harvard College, Cambridge, Mass. He served in the Parliamentary (Parliament) army during the English Civil Wars and was a member of Parliament during Oliver Cromwell's Protectorate, but in 1660 he supported the restoration of the Stuart monarchy. In 1661 King Charles II made him envoy to Holland, England's commercial rival. The Second Dutch War (Anglo-Dutch Wars) of 1665–67 was partially the result of Downing's diplomatic intransigence. As a member of the House of Commons in 1665, he was responsible for a proviso to a subsidy bill (i.e., a bill whereby Parliament granted funds to the king for special needs) which stipulated that the funds be used solely for the war—a case that marked the effective beginning of the process of using funds solely for the specific purposes stated in the legislative appropriation. Downing's appointment as secretary of the newly formed treasury commission in 1667 enabled him to introduce new accounting procedures that left a lasting mark on the British treasury. In 1671 Downing was sent to Holland with instructions to provoke another conflict. His behaviour so infuriated the Dutch that he fled for his life, but Charles had him imprisoned briefly for deserting his post. After his release he continued to hold high financial offices until his death.