Some secondaries are engineering moves of their most challenging students to neighbouring schools, in order to boost their own GCSE league table scores, new research suggests.

The tactic has been uncovered by an analysis of government data, which indicates that academies, particularly in London, are disproportionately more likely to ask pupils to move to another school before they sit GCSEs than local-authority-maintained schools.

Education Datalab, which conducted the research, is calling for an overhaul of the government’s GCSE performance measure to better reflect the entire educational experience of individual students.

The proposal would re-weight each school’s GCSE scores according to the number of terms students spent there, which Education Datalab says would paint a dramatically different picture.

Dr Rebecca Allen, a director at Education Datalab who led the research, said the moves were a “significant issue” in some parts of the country and were causing “great damage” to the educational opportunities of many of the most vulnerable pupils.

She said the data revealed a clear pattern of children moving from particular schools before taking their GCSEs.

“When we reran the performance data based on a student’s time in school, there were enormous changes to some schools’ performance,” Dr Allen said. “This was overwhelmingly a London problem and it was happening much more frequently in academies.

“Those schools that saw a massive fall in the proportion of students gaining five good GCSEs were almost all academies,” Dr Allen added.

The Department for Education said there was “no incentive” for schools to move students on.

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