The timing could not have been more embarrassing for university vice-chancellors. Their lecturing staff had just started a boycott of exams in protest over pay - a move which could mean thousands of students not getting their degrees marked this summer - then a survey dropped through the letter-box showing that their own pay had risen by 25 per cent over the past three years, with the result that 33 were earning more than the Prime Minister.
Cue furious reaction from the lecturers and, according to the unions, growing determination from their members to back militant action over pay.
The survey, conducted annually by the Times Higher Education Supplement and published today, revealed that two vice-chancellors are now earning more than £300,000 a year: Professor Laura Tyson, dean of the London Business School, on £310,000 a year, and Sir Richard Sykes, provost of Imperial College London, on £305,000 a year.
On average, the vice-chancellors received an 8 per cent pay rise last year and 25 per cent since 2001. So far no offer has been made to the unions who are seeking a 20 per cent rise phased in over the next three years.
The biggest rises were awarded to the vice-chancellors of Cardiff and Surrey - each of whose pay has gone up by 61 per cent over the past three years.
John Hood, vice-chancellor of Oxford University, earns 58 per cent more than his predecessor did three years ago. A total of 18 vice-chancellors now earn more than £200,000 a year.
The response from the Association of University Teachers - which, with its sister union NATFHE, staged a one-day strike over pay earlier this year - was to write to the Education Secretary, Ruth Kelly, demanding an inquiry "into the murky world of university vice-chancellors' pay".
The union guaranteed to call off its action if members were granted pay-rise parity with the vice-chancellors - 25 per cent over three years. Otherwise action would continue.
Sally Hunt, the AUT general secretary, said she was demanding an investigation into the pay rises "so everyone can see just what vice-chancellors have done to warrant the huge salaries the tax-payer gives them".
She added: "Why do they receive these whacking great rises? They should be subjected to performance-related pay, like their staff are."
In a joint statement, Universities UK - the body which represents vice-chancellors - and the University and Colleges Employers' Association - which handles negotiations with the unions, said the vice-chancellors did "a demanding job as chief executives of complex multimillion-pound organisations" and "their remuneration packages reflect what it takes to attract, retain and reward individuals of sufficient calibre, experience and talent in a growing sector".
They said the average rise for vice-chancellors last year was "well below the average for chief executives in both the public and private sectors" and most academic and support staff had received increases last year of between 6 per cent and 7 per cent.
Heads in the £300,000 bracket
*Professor Laura Tyson, dean of the London Business School, is Britain's highest paid vice-chancellor on £310,000.
The 58-year-old former senior policy adviser to Bill Clinton when he was US President, says her lifestyle rules out hobbies. "I do not have much spare time. I use it to work," she says.
She has been head of the LBS - preparing students to be business leaders - for five years but is quitting to go back to the US. She is joining the Haas School of Business in California part time, continuing in London as a visiting professor.
Since her arrival in Britain she is best known for a report two years ago for the Department for Trade and Industry on how to break the old boy stranglehold in company boardrooms. She believes her report has led to more and more senior appointments in the UK being done in a rigorous way rather than relying on the "old boy" network.
She was educated at Smith College, Massachusetts, and then took a PhD in economics at the Massachusetts Institute of Technology. She sits on the boards of Morgan Stanley, Eastman Kodak and SBS Communications.
Her 22-year-old son is studying media and politics at the London School of Economics.