Oxford University has been accused of relying on academics on “Deliveroo-style” and precarious fixed-term contracts to give the majority of its tutorials, after new research revealed just a third of lessons are taught by full-time professors.

Data obtained through freedom of information requests by the University and College Union and shared exclusively with the Observer reveals that about 61% of core tutorial teaching is done by academics on fixed-term contracts or in hourly-paid roles. The union says that pay is based mainly on contact hours with students, but once preparation, marking and supporting students are taken into account, this often falls below the minimum wage in real terms.

The new figures, which are based on responses from 24 Oxford colleges, show that in 2023-24 one in five tutorials (20%) were taught by hourly-paid tutors – typically PhD students or academics at the start of their career. Meanwhile permanent full-time professors taught around 34% of tutorials.

Jo Grady, the general secretary of the UCU, said: “Oxford’s colleges have endowments stretching back to the middle ages, so it is nothing short of scandalous that many of the academics leading tutorials are kept on ‘Deliveroo-style’ contracts.”

She added that students and their parents would be “rightly outraged” to discover that a university that markets itself as one of the most prestigious in the world “props up its tutorial system with academics exploited into working on poverty pay”.

One of Oxford’s top colleges, Christ Church, which had an income of £42.6m in 2022-23, is currently advertising a stipendiary lectureship in modern European history for £15,244 to £16,983. The one-year role, taking over an associate professor’s tutorial teaching, student support and running and marking exams for a year while they are on secondment, was originally listed as a full-time position, which would have meant an hourly rate substantially below the minimum wage.

When contacted by the Observer, the college said it was an error and removed the words “full-time”. It said the post covers five teaching hours per week as well as other duties, but they did not clarify how many hours of work the job entails in total.

The union said stipendiary lecturers, who did 38% of tutorial teaching last year according to UCU’s data, are paid at below the university’s recommended minimum grade for academic staff and usually do many hours of extra work that is effectively unpaid.

Professor Martin Williams, pro-vice chancellor for education, said: “The academic quality of an Oxford education is extremely high, with the university rated first for teaching in the most recent UK national student survey results. We recognise that this is based on our committed academics and staff at all levels. We are determined that they are all rewarded and supported appropriately.”

Oxford’s vice-chancellor, Prof Irene Tracey, ordered a review of pay and conditions when she took over in January 2023, with the intention of “easing the pressure” young academics were under. However, the review did not include staff hired solely by colleges to teach tutorials.

Williams said the review’s “far-reaching” recommendations, which include an “Oxford weighting” payment, were already being implemented. “Our initial focus is on areas of greatest need and impact, particularly for our lowest paid staff.”

A PhD student who teaches tutorials at an Oxford college, at an hourly rate of around £37 for two students, said: “I love the teaching, it’s the pay that’s the problem. It’s a joke among people at other universities. They say: ‘Wow, you’re teaching at Oxford. But they don’t really pay you, do they?’ ”

Speaking on condition of anonymity, the student added that he also taught at a London institution two days a week. “I essentially do that to finance the teaching at Oxford.”

He said there was a “feeling of prestige” to being given a lectureship role for an Oxford college because the job came with perks such as being able to chat to senior academics and dining at the high table a few times a week. “But then the pay cheque comes, and you don’t have much to show for it.”

A humanities tutor at another Oxford college described the tutorial system as “incredibly labour intensive and also incredibly exploitative”. “Given that this teaching is Oxford’s big selling point to undergraduates it is a very particular form of hypocrisy,” he said.

The tutor said colleges claimed to include preparation hours in calculations of pay, but this fell “woefully short”. “To do this teaching well requires a large amount of reading. It can be exciting, but it is always gruelling. And most of this work is never paid for.

“I’m aware of tutors who have tried to invoice for more to cover the preparation and marking but have been met with not only a refusal but also the threat that their hours might be removed,” he said.

A college stipendiary lecturer, who described himself as “one of the lucky ones” because he wasn’t on hourly pay, said when he filled in timesheets for one term’s tutorial teaching he discovered that “less than 15% of the hours I had actually spent, which included preparing the course and helping students, were claimable”.

He said: “I don’t think people outside understand who is teaching tutorials and how many tutors are on casual contracts or no contracts at all.”