The Transport Act 1947 set out the nationalisation of the rail network, as part of a plan by Clement Attlee's Labour Government to nationalise public transport. The London Underground, some industrial lines and some remaining light railways like Shropshire and Montgomeryshire Railway were again excluded. For a short time, during World War II, the Shropshire and Montgomeryshire Railway line was taken over by the military. After the war the line re-opened to public use in 1946. The Bicester Military Railway had been built by the government in 1941.