Before revision: The Traffic and Environmental Zone, commonly known as the "ring of URL is the security and surveillance cordon consisting of road barriers, checkpoints and several hundred CCTV cameras surrounding the City of London, the financial district at the heart of Greater London.
After revision: The Traffic and Environmental Zone, commonly known as the "ring of steel", is the security and surveillance cordon consisting of road barriers, checkpoints and several hundred CCTV cameras surrounding the City of London, the financial district at the heart of Greater London.