Blisworth Tunnel 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 on the UK canal network after Standedge Tunnel and Dudley Tunnel (and the ninth-longest canal tunnel in the world). At its deepest point it is "ca."143 feet ("ca."43m) below ground level. The tunnel
Netherton Tunnel Branch Canal was later converted to electricity and it is now unlit. The air vents that run along the line of the tunnel and provide ventilation, and a shaft of light into the canal, are known by the locals as "pepper pots", because of their shape. They are brick-lined and the openings are covered by an iron frame or grill. The wide bore and good ventilation mean that boats using the tunnel today are allowed to use the power of their internal combustion engines, which is prohibited in the narrower Dudley Tunnel. The tunnel cost £302,000 as opposed to the £238,000 estimate