Blisworth Tunnel sections lined with pre-cast concrete rings. It was also used to test out the materials that were later used on the Channel Tunnel. An unused ring is on display near the south portal. Blisworth Tunnel Blisworth Tunnel is a canal tunnel on the Grand Union Canal in Northamptonshire, England, between the villages of Stoke Bruerne at the southern end and Blisworth at the northern end. The northern end is about from the northern end of the Grand Junction Canal at Braunston, Northamptonshire and the southern end about . At 3,076 yards (2,813m) long it is the third-longest navigable canal tunnel
Southampton Tunnel partial construction of the Salisbury and Southampton Canal tunnel, which the railway tunnel crosses at an acute angle and slightly higher. Because the canal tunnel was lined with clay "puddle" it collects water which ends up in the rail tunnel making the latter very wet. In the 1960s an access was cut into the canal tunnel in order to examine it, although this was later sealed behind a new segmental wall structure when, between 1983 and 1985, the tunnel underwent extensive engineering works and the line through it was worked as a single line for long periods while remedial work