Chemistry, physics and biology, each with 9,000-10,000 entries, are exceeded only by English (30,748) and maths (20,546) in the number of entries for this year’s Highers, which begin on May 13 - a similar pattern to the past two years. At Advanced Higher, the five most popular subjects are maths, chemistry, biology, English and physics.

Mike Haggerty, spokesman for the Scottish Qualifications Authority, said the trend towards a strong uptake in science had been evident for some time.

“This shows two things: that there is a stability in the system which we welcome, and that Scottish candidates in Scottish centres retain their focus on the subjects in which Scottish traditional strengths have been built.”

But Stuart Farmer, chairman of the Association of Science Education in Scotland, said that while figures for physics, chemistry and biology uptake at Higher looked healthy, science teachers would still like to see an improvement.

There were also concerns that too many pupils were sitting only one science subject rather than creating a solid base of at least two. “Although the numbers taking Advanced Higher are still reasonably healthy in relative terms, the numbers that go on to university and take pure sciences drop alarmingly. A lot of pupils are studying sciences because they are a good thing to have on their CV,” Mr Farmer said.

Entries for Highers overall have risen from 58,000 last year to 61,000 this year. The least popular subjects are - hospitality: reception and accommodation operations (4); hospitality: food and drink service (5); Gaelic learners: listening and talking (6); music with accompanying (9); and building services (13).

This year’s figures show virtually no change in entries for Standard grade, for which the exams start on May 3: 63,381 last year compared with 63,371 for 2005.