Young academics may enjoy a boom in job opportunities not seen for a generation as new universities are forced to replace thousands of ageing staff, a new report suggests.
Analysis by The Times Higher reveals a divide across the sector, with former polytechnics far more likely to have high proportions of staff nearing retirement than old research universities.
More than a quarter of full-time academics at Anglia Polytechnic and Westminster universities are due to retire in the next decade, according to statistics compiled by the Higher Education Statistics Agency.
A host of other universities including Middlesex, Manchester Metropolitan, London Metropolitan, East London and Leeds Metropolitan have more than one in five full-time staff aged 55 or over.
In contrast, just over one in ten full-time academics at Bristol, Southampton, Sheffield and Nottingham universities are aged 55 or over. At Imperial College London the figure is just 9 per cent among full-time academics.
For young academics, the figures raise the prospect of better career opportunities in the coming years, according to Mike Shattock, visiting professor at the Institute of Education. He said: "This will be an opportunity (for young academics). Currently, there are a lot of disciplines where new blood is trying to get a job. If we have a hugely expanded undergraduate population and quite a buoyant postgraduate population, we have found that for any academic post there is a load of people trying to get a permanent job.
"A lot of people who would have got a job at 28 years old are getting jobs aged 35. There is a real build-up of problems where we have got people hanging on to their academic career by their fingernails."
The figures reveal contrasts between the research elite - which use research funding to employ young contract researchers - and new institutions where staff are less "marketable" and stay and grow old with the institution.
Some 45 per cent of full-time academics at Imperial are aged 35 or under.
At Cambridge, Oxford and Bristol universities, the equivalent figures are 43 per cent, 40 per cent and 38 per cent respectively. At APU, only one in ten academics is aged 35 or under.
Stephen Court, senior research officer at the Association of University Teachers, said: "The age profile of contract researchers is different from teaching and research academics. A large proportion of staff at (Imperial College, Cambridge, Oxford and Bristol universities) do research only and that tends to give those institutions a younger age profile.
"Where large institutions employ academics who do teaching and research or teaching only, they have higher age profiles. The steady rise in the age profile of academics involved in teaching shows that more needs to be done to recruit the next generation."
Professor Shattock said institutions with young staff profiles were likely to have performed well in the research assessment exercise by encouraging older staff to retire and by investing in young contract researchers.
Institutions that had not expanded student numbers had few opportunities to recruit new staff and had older staff profiles.
Among part-time staff, there are proportionally more older academics in music colleges than elsewhere. At the Royal Academy of Music, 32 per cent of part-time academics are aged 55 and over. Some 96 per cent of its staff are part time.
Edward Gregson, principal of the Royal Northern College of Music and chairman of Conservatoires UK, said: "Many musicians playing in professional orchestras, or singers working in the operatic field, find that their careers come to an end in their mid-fifties. Often it is their volition to have a change of direction... and to give back something to the profession that has provided their livelihoods."
Education, mathematics and civil engineering are the subjects with the oldest academics. More than 30 per cent of academics in these fields are aged 55 and over.