In 1967 it was announced that the "Mersey Tunnel Scheme" was now operational.
[1] The scheme comprised what was claimed to be the largest closed circuit television system for traffic control outside North America, and featured a bank of 22 CRT monitors.
This provided Claire House children's hospice in Wirral with a £20,000 windfall, the money being paid to Merseytravel by Warner Brothers, the makers of the film, for use of the Tunnel as a location.
[3] There is an annual 10k run that passes underneath the Mersey via the Kingsway Tunnel.
This is the only time during the year when one can travel through the tunnel on foot.