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
Netherton Tunnel Branch Canal prior to construction. The main reason for the project being overbudget was the extra works necessitated by the condition of the ground through which the tunnel passes. In 1983, the British Waterways Board had of the brick invert replaced with concrete as a result of the invert rising sufficiently to impede navigation. In 2011, significant cracks were found in part of the tunnel lining. Traffic through the tunnel was limited, as a result. Repair work began early in 2013. The canal runs south-west from the BCN New Main Line at Dudley Port Junction and under the Old Main Line at