Experience is important in all walks of life, but particularly so in academia. A report, published in 1984 by the then University Grants Committee, suggested that an ideal age profile was 40 per cent of staff aged 50 and over, 40 per cent between 35 and 49 years, and 20 per cent under 35.
Last October, the Higher Education Funding Council for England reviewed the issue and concluded that universities are moving towards this ideal age profile.
The problem, however, is that many staff are concentrated within a narrow age bracket. A number of universities have a particularly high number of academics aged over 55.
According to 1993-94 figures from the University Statistical Record, nine universities have 20 per cent or more of their teaching staff aged over 55.
The situation in former polytechnics is better: the HEFCE cites 27 per cent aged 50 or over for that sector, against 34 per cent for the old universities (1993 figures).
Unfortunately, more recent figures are not available in this level of detail. Universities agree, however, that the problem is not the age of their staff per se, but how to replace them when they do retire.
The situation is made worse because so many of the most experienced staff will be eligible to retire at the same time.
The massive expansion of the Sixties was followed by years of retrenchment in the Seventies and Eighties. Recruitment fell dramatically. As a consequence, when the current generation of senior staff leave, there will be a reduced pool of lecturers ready for promotion.
This is not a new problem. The UGC ran a "new blood" lecturers' scheme in 1983, followed by a New Academic Appointments Scheme in 1989. Not all subjects were covered, and the HEFCE suggests in its recent report that the schemes "have only a small effect on age distribution".
Funding is still the root cause of the retirement bulge dilemma. Although the HEFCE concludes there is no immediate cause for concern - the staff concentration is among lecturers in their fifties, not their sixties - this may not make enough allowances for universities' financial constraints, or changing patterns of work.
Universities are following commerce and introducing early retirement schemes in ever-increasing numbers. The HEFCE says that the bulk of those retiring do so at 65. This may not be the case for long.
There is a broader social trend towards earlier retirement among professional people, with age 60 rather than 65 the goal for many employees. There is no reason for university lecturers to be different. Older staff are more expensive than their juniors, so there is an incentive among university managers to let senior academics go.
Early retirement programmes, such as those operated by universities including Umist, Lancaster and Nottingham, are open to lecturers from the age of 50. The popularity of the schemes will not be known for several weeks.
At the same time, the Association of University Teachers is concerned that too few junior staff are entering the profession. University recruitment has failed to keep place with university expansion.
The HEFCE points to a rise in new entrants from 1,486 (1989) to 1,686 (1993), but student numbers increased by over a third in that time. The National Postgraduate Committee, which represents doctoral students, says that its members are finding it harder than ever to find a first teaching post.
The HEFCE concedes that some universities may face more serious problems, but says solutions are the responsibility of individual vice-chancellors. Surrey, ranked fifth-highest with staff over 55 by USR, introduced its own "new blood" scheme, with 20 new posts, two years ago. Umist, which has a high proportion of staff in their late forties, is hoping that its early retirement programme will allow it to promote younger staff.
Aston, with 28.4 per cent of staff aged 55 or older in 1993, is also acting. It has moved to more fixed-term contracts, introduced funds to support research for new professors, and is looking at ways to diversify its income, says David Packham, university secretary and registrar.
What universities really crave, however, is stability. This would allow better staff policies. "We would like to be able to plan more in advance. Now we teeter from one year to another," says Mr Packham. "A lot of it does come back to funding."