An acute shortage of staff means thousands of pupils are never taught by a specialist teacher, reports Jon Slater.
Physics is in danger of disappearing from state schools because of a shortage of specialist teachers, an independent report warned this week.
Thousands of pupils are completing GCSE science without being taught by a physics teacher and with little idea about the subject, according to research by Alan Smithers and Pamela Robinson, of Buckingham university.
Professor Smithers said that specialist physics teachers were particularly rare in schools without sixth forms, and many had decided that any science teacher was qualified to teach physics.
The growth of general science had also undermined physics as a separate subject.
Professor Smithers said: "Let us not get into a situation where one of the great branches of knowledge disappears from our schools."
Researchers surveyed more than 400 state and private schools, sixth-form and further education colleges in England. Almost a quarter of 11-16 schools do not have teachers who studied physics at university and only 38 per cent of those who teach the subject are specialists.
The report says the situation is getting worse. More physics teachers aged 30 and under have degrees in biology rather than physics.
One in nine teachers with a degree in physics is teaching other subjects, particularly maths and information and communication technology. Those who are teaching physics are spread unevenly. Grammar schools, private schools with sixth-forms, and sixth-form and FE colleges do best.
Physics teachers in science specialist schools were on average less well qualified than those specialising in arts or languages.
The head of science at a community 11-18 school in the North-east said: "We have advertised for physics teachers three times in the past five years but appointed a biologist or chemist because of the quality of the applicants."
His counterpart at an 11-16 secondary in the West Midlands said: "Staff recruitment and retention is dire. I have been in post for four years and have never been fully staffed. An endless trail of supply teachers usually walks off with little or no coursework achieved."
Another 11-16 school complained it was "almost impossible to attract staff to a school which has no A-level physics to offer".
Professor Peter Main, director of education and science at the Institute of Physics, said: "We urgently need to recruit more specialist physics teachers.
"There are far fewer physicists going into teaching than chemists or biologists. The Government should set specific recruitment targets for the individual sciences (rather than science as a whole) to reflect this and to help focus efforts and teacher recruitment initiatives."
The latest evidence of a crisis in school physics comes just weeks after The TES published a plea from Professor John Holman, director of the National Science Learning Centre, for a pay rise for science teachers to make the profession more attractive.
John Howson, recruitment specialist, said only 29 of 384 science posts in state schools advertised in The TES since September 1 asked for physics teachers.
A spokesman for the Department for Education and Skills said:"Entries for physics GCSEs increased in 2005. But we recognise there is more to do. From next September the total financial package for maths and science trainees rises to pound;14,000 including tax-free bursaries and golden hello payments."
* A second report, to be published on Tuesday, will call for secondaries to put aside health and safety fears about conducting scientific experiments.
Real Science, published by the National Endowment for Science and Technology and the Arts, is expected to warn that fear of litigation and the constraints of the national curriculum are undermining the education of the top scientists of the future.
Physics in schools and colleges is available from www.buckingham.ac.ukeducationresearchceerpublications.htmlNoNosince2000.To join The TES website discussion about physics go to www.tes.co.