Before revision: The "Traffic and Environmental Zone" was officially established in 1993.Corporation of London (1999), "Memorandum by the Corporation of London (IT 134)", House of Commons Select Committee on Environment, Transport and Regional Affairs The term " Ring of Steel " was borrowed from an earlier stage of the Troubles when the centre of Belfast was fortified against attacks; this fortified perimeter was known as the "ring of steel".Coaffee (2004), p. 201 (pdf p. 2) first paragraph.
After revision: The "Traffic and Environmental Zone" was officially established in 1993.Corporation of London (1999), "Memorandum by the Corporation of London (IT 134)", House of Commons Select Committee on Environment, Transport and Regional Affairs The term " ring of steelalso " was borrowed from an earlier stage of the Troubles when the centre of Belfast was fortified against attacks; this fortified perimeter was known as the "ring of steel".Coaffee (2004), p. 201 (pdf p. 2) first paragraph.