In this paper the policies of the Labour Party and the Conservative Party concerning the secondary school reorganisation in the post-war era are dealt with. The 1944 Education Act allowed L. E. A.s to adopt their own system of secondary education, which was not necessarily to be the tripartite system. However, the traditional view prevailed. Even the Labour Ministers of Education held this view. Naturally most L. E A.s chose to adopt the tripartite system advocated by the Ministry. In this situation the Labour Party, apart from the Labour Ministers, worked as the strongest element in the progressive forces. The Labour Party declared its intention of reorganising secondary education along comprehensive lines in 1951. Thereafter the Labour Party continued to express its strong commitment to the comprehensrve principle. In 1965 the Labour Government issued Circular 10/65. This circular, with Circular 10/66, made clear the firm intention of the Labour Party to implement the comprehensive reorganisation. In 1970 the Labour Government introduced a new Education Bill which included provisions for compulsory comprehensive reorganisation. But the Bill did not become an Act. In 1976, however, a new education act was passed. The Education Act of 1976 required L. E. A.s to make their secondary schools non-selective. Thus, the Labour Party finally got legal confirmation of its belief in the comprehensive principle. The Conservative Party represented a powerful element in the traditional forces. While it was in office, the Ministers of Education tried to limit the development of comprehensive schools as little as possible. And the Conservative Party never accepted the concept of the comprehensive school which included the abolition of grammar schools. However, as a result of growing criticism of the selective system, especially of the eleven-plus examination, the Conservative Party had to acknowledge the necessity of some modification. But it still held the view that grammar schools should be preserved and comprehensive schools should co-exist with grammar schools. This belief led the Conservative Government to withdraw Circular 10/65 in 1970 and try to slow down the comprehensrve development. In spite of the attitude of the Coservative Party, as the statistics of the number of comprehensive schools show, the comprehensive school has become the dominant type of secondary school within the public sector.