For years it’s been obvious to teachers, universities and employers that the supply of good and enthusiastic mathematicians and scientists coming out of schools is drying up.

And you do not have to have the brain of Sir Isaac Newton to work out that, if Britain is to keep pace with our competitors in the 21st century, we are probably going to need more natural scientists and mathematicians than graduates capable of writing essays comparing the sociological effects of soap operas and reality TV.

So I applaud a new initiative from the Institute of Physics to give a means-tested pound;1,000 grant to school-leavers joining a physics course at university.

Just before Christmas at my London comprehensive, our prize-giving evening praised the achievements of last summer’s A-level students who left for university. Out of 74 who are now doing degree courses, only two are studying physics and just one has chosen maths.

Yet 10 are on business studies courses, the same number are doing degrees either wholly or partly consisting of sociology, and seven are in the first year of media-related courses.

For me, the one that best sums up the recent trend away from rigorous study in one academic area and towards vague, catch-all piecemeal courses in nothing very much is University College Northampton’s BA in Sports Studies, Media and Popular Culture.

The move away from science won’t come as a surprise in school staff rooms since physics has long been the subject closest to the trap door marked extinction.

In the comprehensives I’ve taught in, in London and the Home Counties, you’ve needed a very high-powered microscope to find a teacher who actually has a degree in physics.

Even those science departments which are fully staffed will usually have an over-supply of biologists, some chemists and, if they’re very lucky, one teacher who studied physics at university. In practice, this means the biologists and chemists take physics lessons.

A similar hidden weakness exists in maths. An Open University study found that, two years ago, more than 60 per cent of maths teachers appointed in schools did not have a degree-level qualification in maths. Hence, in many classrooms, even in popular, over-subscribed schools, algebra and geometry are being taught by teachers whose main area of expertise is economics, history or PE.

To highlight this is not to criticise those teachers who are working outside their main area of expertise. But most in that situation will concede that there are times when weaknesses in their subject knowledge are exposed. And all will acknowledge that for the best to be teased out of young minds, the person at the front of the classroom has to be - yes - a good teacher, but also an expert in their field.

If we want today’s teenagers to become tomorrow’s groundbreaking, or just competently professional, physicists, then surely we have to expose them to people who’ve already been inspired by, and shown a flair for, that subject?

If we don’t, then the vicious circle will spin more rapidly: fewer kids will do A-level physics and maths, fewer will take the subjects at university, which will create an ever shallower pool from which to choose future teachers.

The Government is aware of this impending crisis, at least in the case of maths. Soon after he was appointed, Charles Clarke commissioned an inquiry into maths teaching. In his report, Professor Adrian Smith, formerly head of maths at Nottingham university, is likely to underline the paucity of graduates and teachers, and suggest ways of reversing the trend, all with a cost.

The principle of paying more for teachers in short supply has already been conceded with the pound;6,000 grant during training, and golden hello of pound;4,000 (taxed) a year after qualification. Other financial incentives, management points and the like are also far more abundant in maths and science departments than elsewhere in schools.

This approach will have to be expanded. Money talks. Doing nothing should not be an option.

If Sir Isaac was modest enough to volunteer that he’d only made his discoveries “by standing on the shoulders of giants” then we should recognise that today’s youngsters also need some high quality help if they’re going to follow in his footsteps.

Steve McCormack taught maths in state comprehensives for three years until last month. He has now returned to journalism