A while ago we visited engineering employers in the North-east. Prominent among their concerns was the cost of offering an apprenticeship. In one case, shipbuilding, this was estimated at more than pound;35,000 over three years. In the other, where apprentices became multi-skilled technicians with two HNC awards to show for their achievements, the estimated cost to the company was pound;120,000 over three-and-a-half years.

These are gross costs, including wages and managers’ time when they train young people, as well as the fees for training courses bought from a college, for example. I was not surprised to hear figures this high. We have been told of similar levels of investment - to my relief - in apprentices learning to service passenger aircraft, among others. It’s remarkable how little we all begrudge the cost of learning when it comes to medicine, where we can all picture the incompetent dabbler in our anaesthetised entrails.

We have no more difficulty in imagining the terminal, panic-stricken plunge to earth if an unsupervised, unqualified mechanic were to get his hands on the 0800 from Luton to Lanzarote.

The fact that an advanced modern apprenticeship in a high-technology branch of engineering costs more than a place at a crack medical school seems perfectly reasonable when you consider the risks that must be managed.

It was all the more interesting, then, to read a research paper commissioned by the Department for Education and Skills from the Institute for Employment Research: net costs of modern apprenticeship training to employers (2003). The authors say that the average gross cost of an advanced modern apprenticeship in engineering is pound;46,000 and in construction it is pound;31,000. It is higher in these two traditional areas for apprenticeship than in services, where the average in retail, business and hospitality alike is pound;20-25,000.

Employers would argue about the extent of payback they get from their apprentices in useful work. My two north-eastern engineering employers set the figure emphatically at “zero”.

That seems reasonable if our aero engineering apprentice is prohibited from wielding a spanner on the gleaming Rolls-Royce Trent without the direct supervision of someone who is fully qualified, so that the strict requirements of the statutory regulator are met. It also seems reasonable where a lot of time is spent off-the-job, learning theory. FE college fees were reported by engineering employers to be about pound;4,500 for an intensive, one-year full-time theory programme; all direct outlay, plus wages at around pound;7,000 in the first year.

At the other extreme, however, the Institute for Employment Research concluded that foundation apprenticeships in some low-skilled, low-paid service industry jobs were essentially a cash subsidy to the employer for job creation. These young people were taught nothing. The average net cost of apprenticeships to employers therefore ranged from around pound;15,000 of outlay for an advanced programme in engineering to pound;200 or pound;300 of subsidy for a foundation programme in retail.

All this is interesting but arcane (I hear you stifle a yawn) - my prompt to put my chief inspector’s hat back on.

At the extremes, my inspectors have the challenging job of trying to make valid comparisons between (if you’ll excuse the vernacular) a course in brain surgery and the equivalent of extended work experience. What we might say about the former can appear academic, bureaucratic, hopelessly prescriptive and unrealistic to providers of the latter. Equally, the big high-technology employer gets justifiably hot under the collar when he reads an apparently direct comparison between his heavy investment in a young person’s lifetime career and what appears to be money-for-jam.

All this has taken us into the slippery world of unlimited relativity. Two thirds of 16-year-olds going into advanced modern apprenticeships lack the prior educational attainments to give them a fair chance of success. The Institute of Directors wants to see apprenticeship thrive, urges that nobody should enter one without some decent GCSEs and proposes the abandonment of growth targets until we see standards more firmly established. When is level 3 not level 3? When nobody believes it is a credible precursor to higher education.

We’ve got ourselves into a mess which the task force may well help to pull us out of. Meanwhile, I and mine go out on inspections, week in week out, and meet delightful young people full of life and ambition and employers who care a lot about them. I cannot believe that we can fail to invent some new rules that will banish the white rabbits I sometimes see scurrying past. Rules to bring back a world in which courses that are supposed to be equivalent really are equivalent.

David Sherlock is chief Inspector of adult learning