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
Grand Junction Canal at the rate of two guineas (£2/2s or two pounds and ten pence in decimalised currency) per day plus half a guinea (10s/6d or decimal £0.525) expenses. At the north end, there were problems with the construction of Blisworth Tunnel: quicksand was encountered, and errors made in alignment which meant that the tunnel had a pronounced wiggle. With the opening of Braunston Tunnel, the line was open from the Oxford Canal through to Weedon Bec in June 1796. However, Blisworth Tunnel continued to cause problems, collapsing in January 1796. The canal was opened from Braunston to Blisworth in 1797. The