Grand Junction Canal Nene at Northampton, to the turnpike road at Old Stratford (north-west of the modern Milton Keynes), and to Watford in Hertfordshire: those to Daventry and Watford were not built. The branch to Old Stratford was amended before it was built (see below). The branch to Northampton was delayed as the plans of the Leicestershire and Northamptonshire Union Canal to reach Northampton and thus join with the Grand Junction came to nothing. The link to Northampton was made by a tramroad transferred from Blisworth Tunnel, with the 5-mile (8-kilometre) canal from Gayton being opened in 1815. The link to Leicester was
Kennet and Avon Canal on a tunnel. The tunnel has red brick portals, capped with Bath stone, each with a decorative plaque of Pennant stone. The tunnel was begun in 1806 and finished in 1809. It is lined with English bond brickwork and has a wide bore to cope with the Newbury barges used on the canal. There is no towpath through the tunnel, so walkers and cyclists must walk across the top of the hill. When canal boats were pulled by horses the boatmen had to haul their barges through the tunnel by hand, pulling on chains that ran along the inside walls.