Documents obtained from the Department for Education and Skills show only one in 10 Wearside pupils on free school meals got five GCSEs A*-C, including English and maths, in 2005.

This compares to a success rate of one-in-four for pupils who pay for their meals. There is also a gap in success in further education success between those who pay for their meals and those who don't.

Teacher and Tory councillor Robert Oliver, the Sunderland Conservatives' spokesman on education, said the figures showed the education system wasn't doing enough for children from disadvantaged backgrounds.

He said: "Children with homes with books and an educational environment in them are going to do better, and there's the thing that children of teachers do best of all."

Coun Oliver said parents who had a good education were able to pass on their knowledge to children and were often in a better position to encourage them to learn before they started school, giving them a headstart.

In England, 18 per cent of pupils on free school meals got five GCSEs A*-C including English and maths, compared with 44 per cent of pupils who weren't on school meals.

The figures show in 2005 that there were 523 pupils in their GCSE year in the city that were on free school meals.

Coun Oliver said the issue of pupils on free school meals not achieving as well as other pupils was a national matter and Sunderland was not particularly worse than the rest of the country.

He said schools needed to push pupils forward and ensure that just because they come from poorer homes, they did not have to stay in a lower-income themselves.

He added that giving schools more freedom from Government guidelines and the National Curriculum so they could better serve their communities would help to boost achievement, and the three new academies to be formed in the city could lead the way in doing so.

A spokesman for Sunderland Council said free school meals were used as an indicator of social and economic deprivation, but deprivation was a complex issue that affected individual youngsters in different ways.

He said it could affect a pupil's achievement, but the city had seen a significant improvement in overall achievement over the past three years.

"This improvement is equally true for pupils eligible for Free School Meals, as attainment of five or more A*-C grades at GCSE including English and maths has risen from 11.1 per cent in 2005 to 15.1 per cent in 2006," he said.

"To achieve this improvement we have a number of intervention programmes aimed at pupils at risk of under-achievement, such as Pupils First."