 Under the Railways Act 1921, the NSR was one of the eight major companies designated to form the North Western, Midland and West Scottish Group. This group became the London, Midland and Scottish Railway (LMS). The act came into force on 1 January 1923 but along with the Caledonian Railway, the NSR amalgamation into the LMS was delayed until 1 July 1923 due to certain legal requirements not being completed by the due date.
