First appointed Consul General to Spain in 1724, he became Ambassador five years later, when he negotiated the 1729 Treaty of Seville ending the 1727 to 1729 Anglo-Spanish War. He later agreed the 1739 Convention of Pardo resolving trade and boundary issues in the Caribbean, but political opposition in England meant it was never ratified, leading to the 1739 to 1748 War of Jenkins' Ear.