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
Shrewley Tunnel which crosses the tunnel; having crossed this the path then descends on another ramp to reach the southern portal. The interior of the tunnel is unusually wet and this has led to the creation of flowstone formations. The tunnel runs from the south-east to the north-west. From the northern portal, the canal is level for to the bottom of a flight of five locks at Knowle, which raise the level of the canal by . Kingswood Junction, which connects to the Stratford-upon-Avon Canal occurs about halfway along this stretch. To the south, the canal if level for around to Hatton