A-levels are not fit for purpose and must be reformed to boost the numbers of teenagers taking sciences at university, the Royal Society has warned.
The leading scientific institution is calling for the introduction of an "A-level Baccalaureate" to allow pupils to take a wider range of subjects post-16.
Under the current system, the three A-levels usually taken by students is not enough, as many universities want science and maths undergraduates to have studied more than one science A-level, excluding maths.
The Royal Society's fourth state of the nation report says that the current 16-18 education system results in only a small number of pupils studying maths and science subjects at A-level or equivalent, which impacts on take-up at university.
It found that across the UK in 2009, just 17% of 16-18-year-olds took one or more science A-level, or equivalent qualification.
In the same year, 17% of secondary schools in England did not enter a single pupil for A-level physics. In Wales this figure was 13% and in Northern Ireland it was 43%.
In total, UK universities produce fewer than 10,000 home graduates in science and maths, it warns.
The report says: "Given that higher education institutions tend to want STEM (science, technology, engineering and maths) undergraduates to have taken more than one science subject (excluding mathematics), and that many students would welcome being able to take a wider range and number of subjects at A-level, it is clear that A-levels are not fit for purpose."
Scottish students already take five Highers, the report notes, and both Scotland and Wales have already, or are looking at, Baccalaureate-style qualifications for science and languages for post-16 education.
In England, Education Secretary Michael Gove has announced a new "English Bacc" at GCSE.
"An A-level based Baccalaureate is needed, too," the report says.
The Royal Society's report looked at preparing for transfer from school and college science and maths education to university.
It found that there are too few specialist science and maths teachers in schools. This is due to a lack of science and maths graduates, creating a "self-perpetuating cycle".
Pupils are also receiving inadequate advice and guidance, leading to them picking subjects at A-level that are unsuitable for science and maths degrees.
The report concludes there are a number of reasons why students may not choose to continue studying maths and science after A-level, including lack of enjoyment, perceived difficulty or lack of knowledge about future careers.
It also raises concerns about STEM "deserts" in higher education that make it harder for pupils to continue their studies.
For example, it says, an A-level student in Norwich who wants to take physics at university would have to travel to London to do so.
"As higher education funding is cut and tuition fees rise, these "deserts" may become much more expansive and could even extend to the biological sciences," it says.
Professor Dame Athene Donald FRS, chairman of the Royal Society Education Committee, said: "At a time of economic uncertainty, when science and scientists can play a key role in revitalising the UK's financial outlook, it is deeply worrying to find that numbers of A-level science students are at such low levels.
"It should be a top priority for the Government to reform our education system, reinvigorate science education and inspire the next generation of students to commit to scientific study from school to university."
Schools Minister Nick Gibb said: "The Schools White Paper reflects the importance this Government attaches to these subjects by exploring ways in which to attract the best graduates in science and maths into the teaching profession as well as improving continued professional development for teachers of all subjects.
"We are also seeking the advice of universities and learned societies about how the Government can strengthen science and maths in the National Curriculum and restore rigour in GCSE and A Level exams.
"The English Baccalaureate includes mathematics and science which will drive up participation rates and attainment in these subjects pre and post-16. We are already committed to looking at new ways to encourage the take up of science qualifications, in particular physics, at all levels."Reuse content