Sir Edward Heath's protestations that he was never Margaret Thatcher's warmest admirer - often dismissed as pique - are given substance by documents released this week by the Public Record Office under the 30-year rule.
They show Sir Edward's exasperation with Baroness Thatcher's efforts, in her role as secretary of state for education and science, to reform student unions whose radicalism inevitably attracted Conservative ire.
He was prompted to write to her in early March 1971 following a meeting with the Federation of Conservative Students. The FCS had complained of "alarming examples of discrimination (at York and Southampton) between political clubs and the diversion of union funds to such causes as relief for unofficial strikers", and warned that "extremists in control of several student unions were rapidly tightening their grip".
Sir Edward asked what the Department of Education and Science was doing about it and was not impressed by a reply saying the issue was being worked on. In the margin, he commented: "Yes, but what are they doing? I have to know. I don't expect to be treated like a student."
Baroness Thatcher replied that the FCS's preferred option of creating a registrar of student unions would require legislation. However, she added:
"The matter is being treated with urgency, but I cannot pretend that we yet know all the answers."
Sir Edward was unimpressed and approved the suggestion that his office write to the DES, saying: "Please get your ideas straightened out quickly."
Sir Edward's handwriting, like the man, is hard to read, but his single-word response to DES protestations that making changes for the coming academic year would create practical difficulties looks extremely like "Bunk".
Baroness Thatcher eventually came up with proposals for universities to take over funding and supervision of student activities, but the plans were unpopular, not least with the FCS, chaired by Andrew Neil, now publisher of Scotsman Publications.
Hostility towards them became clear in November, after Mr Neil spoke to the backbench education committee, and chief whip Francis Pym urged that the consultation be as rapid as possible, allowing the government to "get off the hook quickly and relatively painlessly" by dropping the proposals. This it did on December 3 1971.
Other newly released documents show security service concern that the Communist Party of Great Britain regarded eight National Union of Students executive members as "amenable to their policies".
However, the DES held the view that the NUS provided "a legitimate organ of student opinions which is in practice rather more moderate than the public speeches of its leaders might suggest".
In August 1971, Burke Trend, the cabinet secretary, advised against resuming direct MI6 support for moderate student factions, discontinued at the height of unrest in the late 1960s.
There had been greater worry three months earlier when future higher education minister George Walden, then at the Foreign Office, complained that university concentration on academic ability as the criterion for selection for exchange trips to the Soviet Union was to blame for a series of incidents with the authorities. The Cultural Exchange Unit noted that Oxford student Julian Graffy, who had run into trouble in Leningrad, had been rated very highly for language skills and personality, as well as academic ability.
In 1972, the government dropped the Robbins principle of a place for everyone with the ability to benefit as its criterion for planning university numbers - it regarded nursery education as a higher priority.
Baroness Thatcher was to be found arguing that higher education was "valuable for its contribution to the personal development of those who pursue it".
But the December 1972 white paper unveiling these changes omitted all reference to increasing tuition fees and introducing student loans. The cabinet concluding, following Sir Burke's advice, that these issues were "explosive".
Plus ça change.