Blackwall Tunnel from immigrants; the tunnel lining was manufactured in Glasgow, while the manual labour came from provincial England, particularly Yorkshire. The tunnel was officially opened by the Prince of Wales on 22 May 1897. The total cost of the tunnel was £1.4 M and 800 men were employed in its construction, during which seven deaths were recorded. The southern entrance gateway to the tunnel, also known as Southern Tunnel House, was designed by LCC architect Thomas Blashill and was built just before the tunnel was completed. It comprises two floors with an attic. Today the western bore is only used for
Channel Tunnel techniques from the oil industry were employed. Tunnelling was a major engineering challenge, with the only precedent being the undersea Seikan Tunnel in Japan, which opened in 1988. A serious risk with underwater tunnels is major water inflow due to the pressure from the sea above, under weak ground conditions. The tunnel also had the challenge of time: being privately funded, early financial return was paramount. The objective was to construct two rail tunnels, apart, in length; a service tunnel between the two main ones; pairs of cross-passages linking the rail tunnels to the service one at spacing; piston relief