The London, Midland and Scottish Railway Company was formed at the Grouping of Britain's railways in January 1923 when the 'Big Four' companies were established - the other three being the London and North Eastern, Southern and Great Western Railways. The LMS was the largest of all, in fact it was the largest joint stock company in the world for a time, and the only one to reach into England, Ireland, Scotland and Wales. When the railways were nationalised on 1st January 1948, LMS officers and practices took predominant roles in British Railways and the Company's spirit lived on.