Comprehensive schools could have been introduced at no extra cost without reducing educational quality, according to secret Labour Cabinet discussions leading up to the introduction of the historic 1965 circular requiring local authorities to reorganise.

Cabinet records made available this week at the Public Record Office under the 30-year Rule show minimal discussion of the comprehensivation policy. No dissent was recorded in Cabinet over a policy which “need not necessitate additional expenditure”, notes a minute dated January 19, 1965. “Although reorganisation might proceed faster if local authorities could be given financial help in overcoming particular difficulties, inability to find the extra money would not prejudice its quality.”

Members of the Cabinet, headed by Harold Wilson, who died last year, were in any case primed with arguments to use against doubters. Michael Stewart, MP for Fulham and later Foreign Secretary, brought a long memorandum to Cabinet. It urged Labour ministers to deny charges that they were destroying the grammar schools. Rather, comprehensives would extend the grammar school curriculum. “In my view, the essence of a grammar school is that it provided that kind of academic education which we now call ‘grammar’ education. It does not cease to do this when it widens its range of studies to meet the needs of pupils now excluded by the ‘11-plus’.”

The Labour Cabinet had been elected with a slim majority in October 1964, on a manifesto promising to end the damaging effects of selection at age 11. Yet it was anxious to still doubts among its supporters in local government. The key response to the allegation that Labour was suppressing local autonomy was that “people tend to move from one part of the country to another more than they did in the past and this tendency will increase: it is a duty of the central Government, in the interests of children, to see that local divergences in education are not too great.”

Labour policy was to threaten legislation if the circular did not encourage enough councils to move to a comprehensive system. The then Department of Education and Science circulated a note arguing that if there were no mention of legislation, “many authorities would delay action in the hope of a change in policy”.

A number of grammar schools, mainly in London, were identified for the Cabinet as potential centres of opposition to compulsory comprehensivation. These included William Ellis, Camden School for Girls, Mary Datchelor Girls and Central Foundation Girls. “It will be the tactic of the Opposition to magnify them in the hope of permanently obstructing comprehensive reorganisation without committing themselves to an out-and-out defence of separatism and the 11- plus.”

During January 1965, Tony Crosland took over from Michael Stewart as Education Secretary. According to his widow, Susan Crosland, he vowed (using an expletive) to get rid of every grammar school in England.

The Cabinet minutes, however, show him worried about education spending and how to conceal the prediction that by 1970 Labour would have failed to cut class sizes below their mid-Sixties level. Crosland, educated at Highgate School and Cambridge, also started to focus on integrating the public schools into the state system. The Labour Cabinet started discussing how it could ensure the acceptability of the recommendations of the independent commission it planned to appoint.

In the event, Sir John Newsom, the former chief education office of Hertfordshire, was appointed to chair the commission, which was later wound up. Equally, Labour’s thoughts about reducing the privileges of the Oxbridge colleges - the Cabinet discussed ways of persuading them to give fewer places to public school candidates - never saw the light of day.

Harold Wilson did commission a white paper on the arts, which argued that better school buildings and furniture would encourage more artistic appreciation among the young. The white paper was written by Aneurin Bevan’s widow Jennie Lee, who became the first minister for the arts.