Physical connection with the Stour Valley Railway at Haverhill was provided in 1865, and although close relations were maintained with the Great Eastern Railway, the Colne Valley and Halstead Railway remained completely independent until it became part of the London and North Eastern Railway in the 1923 regrouping.
The Colne Valley and Halstead Railway was connected to the Stour Valley Railway at Haverhill in 1865, maintaining close relationships with the Great Eastern Railway. However, it remained an independent entity until it merged with the London and North Eastern Railway as part of a broader reorganization in 1923.