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
Whilton Locks Braunston, which was long, and the other to the south at Blisworth, which was long. Despite encountering quicksands in Braunston Tunnel, it was finished on 21 June 1796, and the canal opened to Weedon Bec, around to the south of the locks. Shortly afterwards, it was extended further south to Blisworth, but there were serious problems with Blisworth Tunnel, which had failed in January 1796. William Jessop was the engineer and wanted to abandon the idea of a tunnel. He proposed to build 29 locks to get beyond Blisworth, but was persuaded to try a different alignment by three engineers