Margaret Thatcher, doyenne of selection and choice in education, failed to save selective schools in Glasgow and Edinburgh from being assimilated into an emerging comprehensive system in early 1973.
Scottish Office papers released under the 30-year rule reveal a raging battle within the Conservative Party over the demise of selective schools such as the High School of Glasgow, Hillhead High and Allan Glen's in Glasgow, and the Royal High in Edinburgh.
By May that year, government policies on education were even condemned by the Scottish Tory Party conference and up-and-coming right-wing MPs such as Teddy Taylor and local politicians such as Brian Meek, the Edinburgh councillor.
The future Lady Thatcher, as Secretary for Education and Science south of the border, was regularly updated by Scottish Office ministers about plans by the cities' Labour-controlled councils to end selection in a limited number of primaries and secondaries.
Fifteen years later as Prime Minister, she intervened to prevent the demise of Paisley Grammar through a planned merger, introducing special legislation designed to increase the powers of ministers over closures. But as Education Secretary, when she was widely known as the Milk Snatcher for ending universal free school milk, other priorities took precedence over the ending of selection by ability.
Tory policy throughout Britain was driven by the imperative to set councils free to run education as they saw fit. Gordon Campbell, the Scottish Secretary, and Hector Monro, the education minister, explained that the city authorities were perfectly within their rights to end selection. There was no challenge to them, provided they were running an efficient and effective service.
On February 22, 1973, Mr Campbell wrote to Mrs Thatcher: "The proposals have given rise to a large volume of objections from parents and others who wish to see no change but I am safeguarding the positions of existing pupils.
"Naturally I regret that schools of good reputation and in one case of long-standing should be unable to continue as they are, but there are no good educational grounds for objections to the proposals which bring these schools into the general pattern both in Glasgow and now in Scotland generally. The large majority of teachers' representatives in Scotland are in favour of the proposals."
Mr Campbell also advised the future Foreign Secretary Douglas Hurd, then political secretary to Edward Heath, the Prime Minister, that he had no intention of telling authorities what to do after approving the closure of the High School of Glasgow (later to go independent) in March 1973.
"As you know, however, it is the Government's declared policy to give education authorities as much freedom as possible to decide for themselves the form of secondary education best for their areas and not to seek to impose any particular form of secondary organisation on them," Mr Campbell wrote.
He told Mr Heath: "I have informed Mrs Thatcher of my intention and she accepts that it should produce no repercussions south of the border."
Tory councillors in Glasgow saw it differently and in December 1972 published an 84-page document condemning the city's plans. Len Turpie, a Tory campaigner, said: "The plain fact is that selection is inevitable in all education, from P1 to the university postgraduate stage, and while no one would for a moment seek to deny equality of opportunity to all, it is conveniently forgotten that there is not, and never will be, equality of ability."
Mr Turpie argued that selective schools were open to pupils across the city, provided they passed the entrance test. Selective schools were therefore a socially integrating force, unlike area comprehensives which drew from a narrow social range. "The test of merit will be replaced by a test of wealth," Mr Turpie warned.
Affluent parents would buy into the independent sector, leaving those from poorer families with their neighbourhood secondary.
But the inspectorate remained highly critical of selective schools and accused them of "creaming off" able pupils. "There are grounds for believing that considerable boredom exists within the walls of the selective establishments," inspectors advised.
They highlighted the "disappointing absence of initiative" in modern languages, engineering science, the arts and social subjects. Apart from Notre Dame, able pupils were not challenged enough and lower ability pupils - although still among the more able overall - performed less well than they should have.
Selectives had ageing, traditional staff who were reluctant to change, and they had not brought in ambitious, young teachers.
Nevertheless, some 30 years in advance of Jack McConnell's pledge as First Minister to shake up comprehensive education, HMI stated: "We concede the need for the comprehensive system to diversify and become more flexible.
The signs suggest this dynamism is already at work within certain sectors of the system."
What inspectors wanted was more focus on senior pupils, the development of the common course in S1 and S2, and appropriate courses for pupils in S3 and S4 who were now forced to stay on until they were 16.
Across in the capital, Labour, led by George Foulkes, Edinburgh's education convener, was intent on ending selection at the Royal High, James Gillespie's High School for Girls and Trinity Academy. At one stage, the Merchant Company, which runs several city independent schools, was invited to take over James Gillespie's. It refused.
Brian Meek, a leading Tory opponent, demanded ministers intervene to preserve the three schools but had little success. Thirty years later, Mr Meek remains a Tory councillor and Herald journalist. Mr Foulkes went on to become Labour MP for Ayr and a UK minister in Tony Blair's early administrations.
* Scottish Education Department officials meanwhile were reporting that the Educational Institute of Scotland, the largest union, was not entirely committed to ending selection. "The break-up of a good school can hardly be regarded as furthering the progress of education," the union said.
EISofficials advocated turning the threatened schools into senior high schools, as had been done in Fife, or re-establishing them as schools for gifted children.