The critical shortage of physics and chemistry teachers cannot be remedied by encouraging young scientists into teaching, but only through pricey investment in retraining existing teachers.

It would cost an estimated pound;24 million a year until 2014 to retrain enough science and biology teachers, and to compensate schools for their absence, said Professor John Howson, the author of a report commissioned by the Gatsby Charitable Foundation.

Even then, the scheme’s success would depend on whether enough young science teachers were willing to retrain in a new speciality.

The report criticising the lack of focus on hard sciences comes hard on the heels of concerted criticism this week of “dumbing down” in the new general science GCSE.

Critics included Baroness Warnock, the philosopher behind Britain’s embryo research laws, and Sir Richard Sykes, the rector of Imperial college, who said that universities might not accept the new qualification.

Edgar Jenkins, emeritus professor of education at the University of Leeds, told The TES that Britain and Europe were falling behind countries like India and China, which were producing vast numbers of scientists.

Where once children modelled themselves on famous scientists and engineers, he said, they now wanted to be pop singers or television stars. The only times universities saw an upsurge in science enrolments was with the success of TV shows like CSI, a US drama about forensic scientists.

But a Department for Education and Skills spokeswoman insisted the problem was being addressed, with increasing numbers of science students at school and university, and numbers of trainee physics teachers doubling. Over the next two years it would spend pound;30m recruiting 3,000 extra science teachers, she said.

The Treasury has proposed an accredited diploma to retrain existing science teachers with the deep subject knowledge needed to specialise, and sought advice on providing them with financial incentives.

The Gatsby report is being considered by the DfES and the DTI’s office of science and innovation, headed by Lord Sainsbury, the science minister.

The Gatsby Charitable Foundation is one of Lord Sainsbury’s family charities, though the foundation says he was not involved in commissioning the study.

Lord Sainsbury has regularly expressed concern about the shortage of science teachers. “We need more science graduates to go into teaching to inspire the next generation,” he said.

The report will put pressure on the DfES which, according to the report, failed to set specific science training targets or to change its attitude to target physics and chemistry specifically.

The Treasury’s goal for 2014 is that 25 per cent of science teachers will be physicists, 31 per cent chemists and the remainder biologists (a 6 per cent increase in physics and chemistry).

But the report observes that university cutbacks, like the pending closure of Reading university’s physics department and Surrey university’s chemistry department, will make meeting that target more difficult.

Those science students that do graduate are being offered increasingly lucrative salaries in the private sector, tempting in an era of increased student debt.

The pay and recruitment of science teachers: www.educationdatasurveys.org.uk