With his partner, Sir Thomas Phillips (q.v.), who succeeded him as town clerk, Prothero was entrusted with the legal work that was entailed in the promotion of bills for the improvement of the town, its streets and highways, port and harbour. He thus became very wealthy, and was not over scrupulous in his methods of acquiring riches. ‘A pugnacious and domineering man,’ he was accused of sharp practice and of extortionate charges by his arch-enemy, John Frost (q.v.), the chartist, once a town councillor, magistrate and mayor, in many published letters which delighted the victimized inhabitants of Newport. He set up as a banker, and was treasurer of the Caerleon Charity, which owned large property that was very rich in minerals, and as a slate and timber merchant he supplied the Charity with the necessary materials. He and Thomas Powell (q.v. in App.) were the largest coal exporters in Newport, and were accused of forming a coal-selling monopoly. At one time he was under-sheriff, and packed the grand jury to secure a verdict against his antagonist, John Frost. His residence was, at first, ‘The Friars’ and, later, ‘Malpas Court,’ which long remained in the possession of his family. He was high sheriff of the county in 1846. He d. suddenly in London 24 April 1853, age 73. He had been twice married. Two of his grandsons, Sir GEORGE WALTER PROTHERO (1848-1922), historian, and ROWLAND EDMUND PROTHERO, baron Ernle (1851-1937), administrator and author, are commemorated in D.N.B. Supplements.