“We are looking to appoint a geography specialist to join our humanities team. The successful applicant may also be expected to teach a small amount of key stage 3 history,” the job advert read.

History, I thought, pausing to consider my suitability. Well, I am a geography specialist…but I’m sure I can deliver one or two lessons on the Romans to some eager Year 7s. How hard can it be?

Like many new graduates, I was excited by the challenge of securing my first teaching post ─ and even by the idea of adapting my newfound skills to a second subject.

I gave it little consideration at the time, but more than a decade on, I can now see that the school in question deemed it significantly important to notify candidates of the possibility of teaching outside their specialism. Oh, how times have changed.

At the same school that once saw fit to warn that a teacher “may” have to diversify, I know of members of staff who are now teaching three or four different subjects. One former colleague is currently delivering four different GCSE syllabuses, including food technology and food nutrition, as well as teaching humanities at KS3.

“Staff are just getting spread too thin,” he told me, “Dealing with so many schemes of work, different departmental meetings and trying to get the time to research new content is impossible. In the end, some things just don’t get done.”

His situation is by no means an isolated case. Data taken from the most recent school workforce census indicates that only 65.1 per cent of geography, 72.4 per cent of history and 62.5 per cent of physics teachers hold a relevant post A-level qualification for the subject they teach. For maths, the figure was 73.7 per cent of teachers and for English, 77.6 per cent.

The burden of teaching outside of your subject specialism

This trend places additional burdens on already busy teachers working outside of their subject, as it requires them to quickly upskill in a new area.

It also increases workload for subject leaders. In my penultimate year in teaching, I was running two departments across two different schools that were some 13 miles apart, without ever being at either establishment for more than two consecutive days. This was a federation policy that was dictated by finance, but ultimately did not benefit anyone involved.

My timetable was dominated by KS4 and KS5, while the delivery of KS3 geography was left to a collection of colleagues identified as being “under the stipulated period requirement”,  a reluctant mixture of artists, scientists, historians and musicians. Inevitably, this led to more meetings, the provision of lesson plans, activities and differentiated resources and, in some cases, taking on additional lessons.

Surely, it would be seen as ludicrous for a reputable construction company to employ an electrician to fit the plumbing for its properties or for the NHS to employ a heart specialist to carry out brain surgery. Yet it would appear that this Jack-of-all-trades policy is now commonly accepted practice when it comes to education.

In the job specification for today’s teacher, there is almost an expectation that you will teach a second subject, if not three or four. But how often is that made clear in job ads?

This is no way to improve the current crisis of teacher retention. Newly-qualified subject specialists looking to secure their first posts want to impart the knowledge of a subject in which they passionately believe. By forcing them to teach outside of their subject we are laying unstable foundations for their career to come. Is it any surprise, then, that so many choose to leave?

The writer is a former head of geography.