Research into the A-level system and the labour market, published on Saturday, found that former maths students earn between 7% to 11% more than the average for their peer group with similar levels of qualifications in other subjects.

Although researchers have not established why maths in particular should be so sought after, it seems that employers are still attached to mainstream A-levels as the "gold-standard" of post-16 education.

Studying a wider range of subjects has few incentives, say researchers

The Centre for Economic Performance, based at the London School of Economics, has found that despite moves towards a broader A-level curriculum there is no evidence that this makes students more attractive to employers.

Even though there have been calls from employers' organisations for a wider, European-style A-level curriculum, in practice the study found that employers showed no preference for students who had a wider range of qualifications.

In Scotland the system of Highers has already provided a broader curriculum for this age group, but the researchers did not find that employers preferred such qualifications to the current A-level system.

Students who had taken three widely-spread A-levels, such as a science, language and arts subject, were also found not to be at an advantage in employment terms.

The Department for Education is to encourage students in England and Wales to study for additional AS levels (worth half an A-level) in the lower sixth year, to offer a broader curriculum, but the researchers say that there is little incentive for students to take up the extra subjects.

As well as showing no economic benefits, the research also casts doubt on any academic advantage to avoiding early specialisation.