SCOTLAND outperforms other UK countries in core school subjects, according to a major world study.

The survey of 15-year-olds puts Scotland at the top of the list for reading and maths compared with England, Northern Ireland and Wales.

However, the Programme for International Student Assessment (Pisa) shows that, for science, Scotland was slightly behind England.

Overall, Scotland's ­performance has remained similar to previous years both in terms of its score and its international position.

The rankings, by the ­Organisation for Economic Co-operation and Development (OECD), are dominated by Asian school systems - although China so far does not participate as a whole country and is represented by high-performing cities such as Shanghai and Hong Kong.

Singapore, Taiwan, South Korea and Japan are also among the highest ranked across all subjects.

Alasdair Allan, the Minister for Learning, pointed to Scotland's performance against "significant world economies". He also highlighted an ­improvement between children from different economic backgrounds.

He said: "Scottish school ­attainment remains strong, particularly in science and reading. We are performing at least as well as a number of significant world economies across all three areas, reinforcing our international standing in education.

"There is also clear evidence that the attainment gap is being addressed with a reduction in the variation in performance between those pupils classed as disadvantaged and those who aren't."

However, Scottish Labour's education spokeswoman Kezia Dugdale, said: "Disappointingly, these figures show not much has changed in terms of Scottish educational attainment over the past decade.

"We need to use these results to compare ourselves, not with England, but to our global competitors in this increasingly interconnected world. Continuing to stand still while others improve isn't good enough."

However, teaching unions warned against taking the findings of the survey too seriously.

A number of concerns have been raised about the Pisa study in recent years, with critics arguing it only measures a fraction of what is learnt.

Larry Flanagan, general ­secretary of the Educational Institute of Scotland (EIS) teaching union, said: "While this report seeks to measure performance in school education there are significant questions over the testing methods used to gather data and the degree to which like is being compared with like.

"The circumstances in different countries vary widely, and individual nations take significantly different approaches to education in terms of how schools are organised, funded and run.

"There is also concern that, in some countries, a heavy emphasis is placed on preparing pupils to perform well in these tests specifically to boost Pisa rankings."

Alan McKenzie, acting general secretary of the Scottish Secondary Teachers' Association, added: "While the scale of the exercise is immense given the number of nations involved the scope is limited to narrow performance outcomes in three areas."

For maths, Scotland scored 498 points, four higher than next-placed England. For reading, the country scored 506 points, six higher than England and Scotland scored 513 points for science, behind England, which scored 516. Wales performed worst across the three subjects.

The tables are based on data from 510,000 students across the participating countries in 2012.