Concerns have been raised that pupils in deprived areas could be missing out on the opportunity to study more difficult GCSEs as a result of pressure to improve league table performance.
An analysis carried out by the think-tank Open Public Services Network has revealed widespread variation in pupils' access to subjects such as triple science and language GCSEs.
In poor neighbourhoods, young people are either being denied access or strongly encouraged not to take up certain subjects. The think-tank warned this could lead to 'subject deserts' in some areas, where pupils are unable to attend a school that offers the courses they want to study.
Half of the institutions in the North East Lincolnshire Local Education Authority do not offer the triple science GCSE, while over a third of schools in Knowsley (43 per cent), Slough (36 per cent), Kingston upon Hull (38 per cent) and Newcastle (36 per cent) do not enter any pupils for the subject.
In Sussex and Cumbria, however - local authorities with over 30 schools - every institution offers a GCSE in three sciences.
Youngsters in Knowsley are half as likely to be enrolled for a science GCSE as children in Buckinghamshire.
In Kensington, youngsters are four times more likely to be enrolled for a language GCSE than in Middlesbrough, where, on average, only one child in every four takes a language GCSE.
The report, which will be published next week, argues that with a growing number of schools converting to academy status (giving them greater autonomy and freedom to choose their own curriculum), Local Authorities are unlikely to tackle the problem.
It also states that the Department for Education's accountability regime could be incentivising some institutions to offer more limited opportunities to pupils in a bid to boost league table ratings.
Royal Society of the Arts director of public services Charlotte Alldritt said: "Rather than dumbing down our curriculum to achieve better grades, school leaders should be aiming to improve the standard of their teaching so that all children have the chance of going onto the academic or training courses they want and getting the best jobs available."
Posted by Alan Douglas