The study, by Professor Maurice Galton of Homerton College, Cambridge, and expected to be published shortly, has increased ministers' fears that teachers are neglecting pupils' basic skills in the early years of secondary school.
Investigations by government exam advisers at the Qualifications and Curriculum Authority (QCA) also suggest that teachers often underestimate pupils' ability when they move from primary school to secondary school because they do not know enough about them. They teach them things which they already know with the result that they become demotivated and are sometimes switched off education for the rest of their school days.
The study found that around 45 per cent of pupils did less well on a standardised reading test at the end of their first year at secondary school than they did when they left primary school. Research commissioned by the authority came up with similar results and found that pupils of lower ability were more likely to go backwards than average or able pupils.
Ministers are planning a national transfer form detailing individuals' achievements which all pupils would have to take with them from primary to secondary school. At present there is no common format and some secondary schools complain that they are not getting enough detailed information.
Exam advisers began an inquiry into pupils' experiences between the ages of 11 and 14 when they discovered that children were not making the expected progress in national curriculum tests in English, maths and science. The results have been rising more quickly for 11-year-olds than they have for 14-year-olds.
David Hawker, head of curriculum and assessment at the QCA said: "Between the ages of 11 and 14, the gap between boys and girls grows wider as does the gap in attainment between the most able and least able pupils.
"At age 14 we find that fully 10 per cent of pupils are being assessed at the same level of attainment in English, maths and science as they were when they were last assessed at 11. In short, schools need to give serious attention to what goes on at this stage. They need to look again at how the reinforce reading skills. They tend to assume that pupils can read.
"The documentation involved in the transfer process is not terribly well managed. Children are sometimes expected to work at a lower level than they had reached at primary school and that is demotivating."
John Dunford, general secretary of the Secondary Heads Association, said that he was surprised by the findings. Relationships between primary and secondary schools had improved greatly and most secondaries had already targeted children who would need help with reading before they arrived. He suggested that reading might fall back in pupils' first year at secondary school because they were concentrating on a wider range of subjects.
"We must resist any pressure to narrow the curriculum which is what children find exciting about secondary school. But if this causes schools to look at their literacy policies then this will have been useful," he said.Reuse content