University bosses enjoyed salary packages worth more than £272,000 on average last year, as pay for senior leaders rose, a report suggests.
In some cases, vice-chancellors were handed pay rises of more than 10%, according to a new study by the University and College Union (UCU), which calculated that these university leaders took home almost seven times more than the average wages of staff.
In addition, thousands of pounds more was spent by universities on hotels, flights - often first or business class - and other expenses for vice-chancellors, according to a report by the University and College union (UCU).
The union, which obtained the data through freedom of information requests as well as publicly available data, said there were "huge disparities" in pay and pay rises, and called for an open and frank discussion about the issue.
It said it was concerned that staff pay continued to be held down, while bosses enjoyed "inflation-busting" pay hikes.
UCU asked UK universities and colleges a series of questions about vice-chancellors' pay packages, including benefits and pensions, as well as money spent on air fares, hotel accommodation and personal expenses, for the year 2014/15.
The findings show that the average overall salary package for university heads in 2014/15, based on data from 152 institutions, was £272,432. This was up 3% on the year before, when 150 institutions gave figures.
A total of 27 vice-chancellors saw their pay increase by more than 10%, compared to 18 bosses the year before, according to UCU's analysis of the data.
The highest paid was Professor Andrew Hamilton of Oxford University, the figures show, who took home a pay package, including benefits and pension contributions, of £462,000 in 2014/15.
Both Salford and Durham Universities paid a higher amount, having changed their vice-chancellor during the year, the report revealed.
The average spend on airfares for university bosses, with information gathered from 132 institutions, was £8,506.37.
Strathclyde University spend the most, according to UCU's data, paying £41,891 on flights for Professor Sir Jim Mcdonald.
Almost half of all flights taken by vice-chancellors (49.6%) were in business or first class, while 21 university leaders flew exclusively in these two classes.
And the average spend on hotel bills was £2,989.93, the report showed. This was based on data from 128 institutions.
Glasgow Caledonian spent the most on hotels for Professor Pamela Gillies at £19,864.77.
There was a drop in expenditure on both flights and hotels, between 2013/14 and 2014/15 the report suggested.
A different number of institutions responded to each question last year.
UCU general secretary Sally Hunt said: 'The time has finally come for a frank and open discussion about pay and transparency in higher education.
"The huge disparities in the levels of pay and pay rises at the top expose the arbitrary nature of senior pay in our universities.
'While some continue to enjoy inflation-busting pay hikes and all the trimmings of first class flights and luxury hotels, staff pay continues to be held down.
"We will continue to campaign for a proper register of pay and perks at the top of our universities.
"This information must be made readily available and no university should be allowed to get away with not responding to an FoI (Freedom of Information) request."
A total of 18 universities did not respond to the Freedom of Information request.
UK universities are independent institutions but they receive public grants, and students receive government loans to pay tuition fees.
Vice-chancellors' pay has come under the spotlight in recent years, with ministers raising concerns in 2014 about the "substantial upward drift" of salaries.
An Oxford University spokesman said: "According to this year's Times Higher Education World University Rankings, Oxford is the number one university in the UK and number two in the world. It is consistently ranked as one of the two best universities in the UK and among the handful of best universities in the world.
"Its research output is vast, it has more than a billion pounds a year in turnover, not including the colleges and Oxford University Press, and it has great institutional complexity. The vice-chancellor's salary reflects that."
A Glasgow Caledonian University spokesman said: "In excess of £12 million was generated by Glasgow Caledonian University (GCU) through its international activities in 14/15. This requires investment.
"The Principal and Vice-Chancellor plays a leading role in developing research, business, academic and philanthropic partnerships as well as conferring GCU degrees to students in Bangladesh, South Africa and Oman and working at our campuses in London and New York.
"Professor Gillies maximises the value of each business trip by fulfilling a full schedule of engagements to further the interests of the university and Scotland. GCU is transparent in reporting costs incurred and Professor Gillies' travel and accommodation costs are subject to scrutiny by independent governors on the University Court."