 St Clair, fulfilling a promise he had made at the time of his election, then accepted the office of Steward of the Manor of Northstead, disqualifying himself from the House (outright resignation not being possible).Benn returned to the Commons after winning a by-election on 20 August 1963.In the 1964 Government led by Harold Wilson, Benn was Postmaster General, where he oversaw the opening of the Post Office Tower, then the UK's tallest building, and the creations of the Post Bus service and Girobank.