To become a teacher in Massachusetts, the highest-performing state in the US in national tests, you need to have strong subject knowledge. Similarly, in the much-lauded Finnish system, teachers are required to possess a master’s degree unless they are teaching preschool. Research from the Sutton Trust has also emphasised that “solid” knowledge of the subject to be taught is essential for high-quality teaching.

The latest report from the same charity, Teaching by Degrees, however, reveals that new teachers with the greatest subject knowledge - a postgraduate degree - tend to gravitate to independent schools rather than the state sector.

Almost one in 15 teachers in these schools has a PhD compared with one in 40 in the state sector. Richard Sheriff, headteacher of Harrogate Grammar School, is in no doubt of the benefits. “Having clever people teaching kids helps them to be clever,” he says.

So the Researchers in Schools scheme should come as very welcome news. This school-based teacher-training system takes doctoral students who have spurned a career in academia and places them in state schools in very disadvantaged areas. Not only do these PhDs have very deep subject knowledge - some seven years of research and study - but many of them will probably have a fair bit of teaching experience under their belts, too.

In UK universities, the pursuit of subject knowledge is considered to be above everything else. Academics often delegate the teaching duties on their undergraduate courses to doctoral students, while they focus on their research instead. Teaching is downgraded to such an extent that the majority of academics have resisted acquiring any skills or qualifications.

Consumer pressures from fee-paying students are changing all this. Although academics may rate research as more important than teaching, undergraduates value lecturers with formal teaching qualifications far more highly than those who are active researchers.

According to the Higher Education Policy Institute’s UK-wide Student Academic Experience Survey 2015, only 17 per cent of students felt it was most crucial for staff to be pursuing research in their subject, with 39 per cent citing a lecturer’s formal teacher training as being vital. Those studying physics, maths, computer science, languages and engineering were keenest to be taught by a trained teacher.

Some academics have snarkily pointed out that spoon-fed pupils expect a continuation of their school experience, but there is a lesson to be learned here: while it is important for teachers to have good content knowledge, a balance has to be struck.

Knowledge may be the mot du jour, but there are in fact two key findings in the Sutton Trust’s report, What Makes Great Teaching, the other being the quality of instruction that pupils receive.

Academics may arrogantly assume that being passionate about their subject and knowing it inside out is enough. But as many students know to their cost, an expert in their field is not necessarily an expert in communicating it to students.

So by all means, let’s have sages who know their onions, but let’s not forget that it is equally important to know how best to serve them up.

ann.mroz@tesglobal.com