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
Paw Paw Tunnel expected completion date of July 1838. Lee Montgomery, a Methodist minister who had experience from building the canal tunnel for the Union Canal was awarded the contract on March 15, 1836. Construction on the tunnel began in 1836. Unfortunately for Montgomery, the Irish workers were not skilled at tunnel work, so he obtained English masons, English and Welsh miners, and some "Dutch" [i.e. German] labourers. More unfortunately, this caused ethnic tensions which exploded into violence in 1837 and 1838, specifically between the Irish and everyone else; rioters destroyed the tavern at Oldtown, burned shanties, and the like. There were more