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
Blisworth centuries iron ore and limestone were quarried at Blisworth. A limestone quarry began in 1821 north east of the canal tunnel and was connected to a canal wharf at the west end of the tunnel by horse-drawn tramway. The tramway ran from the quarry, across the Stoke Bruerne Road and above the west end of the tunnel. Trains of loaded wagons descended by gravity and empty ones were pulled up by a horse. There was a chute for filling the canal boats from the stone wagons .The quarry was closed in 1912 or 1913. A trial iron ore quarry operated