SCOTLAND'S school system is still riven by social segregation despite nearly 40 years of comprehensive education, a study shows.

It says the attainment gap between 18-year-olds from middle and working-class backgrounds increased between 1985 and 2005.

However, the report also highlighted evidence that the introduction of exam reforms in 1999 - known as Higher Still - had led to a "dramatic rise" in average attainment from lower social class pupils from 2001 to 2005.

Dr Linda Croxford, of Edinburgh University, who compiled the report, said: "All the reforms have been associated with an even more rapid increase in attainment in pupils from middle-class backgrounds.

"That has left us in a position where pupils from higher social classes are still at the forefront when it comes to accessing higher education."