In 1778, Hardenberg was raised to the rank of privy councillor and created a graf (or count). He went back to England, in the hope of obtaining the post of Hanoverian envoy in London; but his wife began an affair with the Prince of Wales, creating so great a scandal that he was forced to leave the Hanoverian service. In 1782 he entered the service of the Duke of Brunswick, and as president of the board of domains displayed a zeal for reform, in the manner approved by the enlightened despots of the century, that rendered him very unpopular with the orthodox clergy and the conservative estates. In Brunswick, too, his position was in the end made untenable by the conduct of his wife, whom he now divorced; he himself, shortly afterwards, marrying a divorced woman.