 His change of surname to Blackett was later confirmed by an Act of Parliament in 1733.He was High Sheriff of Northumberland in 1731–32 and elected Tory Member of Parliament in the British House of Commons for Newcastle-upon-Tyne over seven parliaments from 1734 until his death.He was an Alderman of the City of Newcastle and Mayor five times, in 1735, 1748, 1756, 1764 and 1771.