The number of schools reported for failing to give priority to children in care has soared by three quarters this year, despite the fact it is now illegal.
The figures were revealed this week in the annual report of the Office of the Schools Adjudicator, which settles school admission disputes. It says its overall workload has increased by around 75 per cent, as local authorities have taken a harder line on schools which bend intake rules.
A total of 245 admission objections were referred to adjudicators this year, as opposed to 140 last year. Of these 59 related to schools trying to avoid giving places to children in care, as opposed to 35 the previous year. All but two of the latest objections were upheld.
Regulations were passed this February requiring all admissions authorities to give priority to children in care.
"There can be no arguments about this now," Philip Hunter, chief adjudicator, said. "It is the law that these children must be given priority, and schools must accept this."
Dr Hunter said local authorities had written to schools warning them they would be referred to his office if they tried to avoid taking children from care.
"I hope schools will be better informed and aware of their statutory duties next year," he said.
He said most of the admissions cases were referred to the adjudicator by local authorities, often after reviewing arrangements in all their schools.
The number of objections to schools attempting to reserve places for teachers' children at the expense of local parents increased from 24 in 2005 to 28. However, only 18 of these objections were upheld.
Dr Hunter said where in previous years local authorities and admissions forums had concentrated on setting up systems, they were now taking enforcement of the existing admissions code more seriously.
He said the national debate about admissions, triggered by the consultation on the new code for next year, had raised awareness and led to more referrals.
The workload of the adjudicators is likely to increase greatly when the new code comes in to force, as individual parents will be able to refer cases for the first time. Currently only groups of 10 or more parents can make objections to the adjudicator.
Dr Hunter did not spare local authorities from criticism in his report. He said that the merging of education departments into children's services departments had led to a loss of expertise, particularly in the smaller authorities, needed for complex school reorganisation exercises.
He approved only half the 38 statutory proposals made to him by local authorities - most of them relating to school closures, mergers or, in a few cases, expansion.
Susanna Cheal, chief executive of the Who Cares? Trust, said it was vital that children in care were given opportunities to achieve at good schools.
"Education is the best chance they've got to lead successful lives," she said.
Ms Cheal said schools often underestimated the ability of children in care, or believed that being in care was somehow their fault.
"There is enormous untapped potential in the care population," she added.
In the care green paper published last month, the Government said that educational success was the key to improving later life.