Blisworth Tunnel has no tow path inside, but is wide enough for two narrowboats to pass in opposite directions. Work began in 1793, but errors by contractor left a wiggle in the tunnel, and after three years work it collapsed due to quicksand, claiming the lives of 14 men. It was then decided to begin again with a new tunnel. By the time the rest of the Grand Junction Canal had opened between London and Braunston, Northamptonshire in 1800, apart from the crossing of the River Great Ouse, the section of canal from Blisworth to the lower end of Stoke Bruerne locks
Dudley Tunnel the tunnel pass through a dolerite known locally as Rowley Rag; and through Coal Measures rocks. The Netherton Tunnel follows a parallel route 1½ miles to the south east; it is much larger and has twin towpaths running through it. It was built to ease congestion in the Dudley Tunnel. Dudley Tunnel Dudley Tunnel is a canal tunnel on the Dudley Canal Line No 1, England. At about long, it is now the second longest canal tunnel on the UK canal network today. (Standedge Tunnel is the longest, at , and the Higham and Strood tunnel is now rail only).