It contains a working mechanism for operating the drawbridge and the portcullis. The shield shows a portcullis surmounted by a royal crown. Two semi-octagonal towers flank a passageway protected by a portcullis. On the ground floor, there is a guardroom protected by a portcullis. The portcullis and gate defences are also reconstructions. Modifications to the barbican have removed evidence of a portcullis and its grooves. The reverse shows a Tudor portcullis with chains and a coronet, with the inscription . His emblem was the Tudor rose and the Beaufort portcullis. It was a simple structure, protected by a portcullis and gate. In Scotland, there is a working portcullis at Edinburgh Castle. Opposing the entrance was a second portcullis that led to the rear compound. The entrance was also protected by a portcullis, which could be opened and closed. The symbol used by the Commons consists of a portcullis topped by St Edward's Crown. The quasi-official emblem of the Houses of Parliament is a crowned portcullis. The arch was protected by a portcullis, whose associated grooves are still visible.