Extra classes for children struggling in maths and English have failed to bring them up to the government's required standard, research has shown.

A multi-million pound experiment with summer literacy and numeracy lessons for pupils lagging behind at secondary schools led to less than half reaching level 4, according to a study by academics at King's College, London (KCL).

Professor Margaret Brown, who led the research, said that the figures were estimates and the actual proportion could have been as low as 15%.

She said the problem was the targets set by ministers, not the classes themselves.

Programme extended

The lessons were piloted in 200 schools which were each given �10,000 to run summer sessions as part of the Government's drive to ensure that children do not regress between the ages of 11 and 14.

The programme is now being extended to all comprehensives in England.

But the KCL research, based on an evaluation of 30 of the schools in 17 English local education authorities, showed that less than half the pupils reached the required standard even with the extra help.

Those who did tended to be near the top of the level 3 band in national tests for 11-year-olds or reached level 4 by improving their writing.

Professor Brown said the children obliged to attend the catch-up classes were likely to have been those singled out for remedial work earlier in their school careers.

By the age of 11, their motivation was likely to drop after years of being identified as low achievers, she said.

But instead of concentrating on what they could realistically achieve, teachers had been forced by the targets to try to boost attainment beyond what was possible.

'Scrap targets'

"All our figures show that there's a seven-year spread in the attainment range and it is quite unrealistic to expect most of them to suddenly get up to level 4.

"Scrapping some of the targets would help because some of the teachers felt frustrated that they were going to be judged on not getting children up to level 4 when they had worked terribly hard with them."

Professor Brown, a former member of the task force that helped draw up the national numeracy strategy, said it would be better to measure the improvement in each child's points scores for English and maths.

A spokesman for the Department for Education and Employment said: "Supporting children who need extra help in the first year of secondary education is a central priority.

"Catch-up provision has been trialled and we have refined it in the light of this for the national introduction."