Circular 10/70 was an attempt by Margaret Thatcher as Secretary for Education in 1970 to reverse the effects of Circulars 10/65 (or, the Crosland Circular on account of having been issued by Anthony Crosland as Secretary for Education under Wilson in 1965) and 10/66.
Those circulars had recommended to LEA that they begin the process of conversion to full comprehensive education, in line with Labour government's wishes on the transition to a national comprehensive system.
Circular 10/70 did not fully reverse the effect but empowered LEAs to decide the future of Secondary Education in the area under their authority independently of central government.[1]
Although Thatcher did her best to show that she was not trying to discourage comprehensive education as a system, the withdrawal of 10/65 sparked some notable controversy.
The National Union of Teachers was concerned not only about the implications of the withdrawal but also the lack of consultation which had taken place before the decision: "On the implications of circular 10/70 itself, the deputation expressed the view that it represented an encouragement to local authorities opposed to comprehensive education, and an endorsement of selection at eleven"[2] The concern was that Thatcher was implicitly trying to reinstate grammar schooling as an ideal in the British education system via the back door.