 Undivided from this are numbers 2-4, the Serious Fraud Office, and number 5 Trafalgar Square whose numbering, widely used for official purposes, comes from Cockspur Street — this is the headline part of Canada House, the Canadian High Commission.Numbers 2–4 were the Canadian Military Headquarters from 1939 to 1947.Numbers 6 to 13 are no longer used, having made way for new wider street layouts.