It is almost certainly unlawful, and some say "immoral" and "unforgivable". But a secondary head has admitted that official targets are leading schools to "remove" students who threaten their league table positions because they are at risk of failing.
In a letter seen by TES, Jim Parker, head of Manshead School in Caddington, Bedfordshire, implies that he may have to remove pupils who "may have succeeded", noting that in such situations schools are "encouraged by the need to show that performance targets are met".
He adds that he knows of other schools where "students are asked to leave midway through courses that they have a reasonable chance of passing, but perhaps not at their target grade".
One heads' leader said the ratcheting up of league table demands on schools meant no one should be surprised by the development. "The pressure is being increased, and too much pressure will inevitably mean that some schools will be pushed into focusing more on pupils who can meet their targets," Association of School and College Leaders general secretary Brian Lightman said.
Mr Parker's letter emerged through a dispute that is expected to result in his school being sued by a parent.
Manshead School pupil Glenda Oduro was asked to leave the sixth-form in January, five months before she was due to sit her A-levels. The school cited poor attendance - denied by the then 18-year-old - and concerns that it was "unlikely" she would pass. Mr Parker said she had been given opportunities to catch up on work he said she had missed and had failed to demonstrate she had achieved the necessary standard.
But the Department for Education has said it is "unlawful" for a pupil to be excluded from a school, including a sixth-form, on grounds of attendance or academic performance.
Mr Parker told TES that Glenda had not been officially excluded, but he confirmed that she had not been given the option of staying on. Government guidance says that unofficial exclusions are also "unlawful and schools may be legally liable if they exclude pupils unofficially".
Victoria Oduro, Glenda's mother, described the school's action as "immoral". "I begged the headmaster to allow Glenda to sit her A-levels and he said she no longer had a place. I brought my children up to value education. They want to go to school. We educate prisoners, but my daughter has committed no crime and was denied her right to education.
"They really broke her; she was humiliated. I can't forgive. I really can't. I don't think any parent in this country should have to beg for their child to be educated."
Mr Parker explains his position in the letter to a local MP citing the pressure of targets. "Perhaps it is fair to say that in years gone by we would have allowed students like Glenda the chance to continue," he writes. "There, of course, would have been a strong possibility that they could have failed and in effect wasted two years at school, but other students may have succeeded."
In a TES interview this week the headteacher changed emphasis, saying "it was our view that she (Glenda Oduro) was not going to achieve a pass at all".
Three years ago it emerged that some independent schools were "soft culling" pupils to improve their league table positions. Weaker pupils were either persuaded not to enter exams or to sit them elsewhere as private candidates, so they did not affect a school's score.
Mary Bousted, general secretary of education union the ATL, said: "With the pressure of league tables it is not surprising that some schools are game playing like this. What is surprising is that someone is admitting it."
Mr Parker told TES that pressure on schools was growing "because everything that schools do is measured". But he insisted that had not been a factor in the Glenda Oduro case.
In December 2009, Ofsted noted that a system of tracking pupil progress had been introduced to Manshead's sixth-form. It allowed staff to "quickly identify areas of achievement and to intervene where required", resulting in a rise in the A-level pass rate from 91 to 97 per cent.
A national charity that advises parents on exclusions said that if a school had concerns about a pupil's academic progress it had a responsibility to help them. "They could offer more support or suggest a more appropriate course," Sam Murray from the Advisory Centre for Education said. "Not say, `You might fail so you have to leave'. There may be pressure to meet targets, but shouldn't helping a child to meet their potential be more important?"
Ms Murray said parents often wrongly assumed that pupils had no protection against wrongful exclusion from school sixth-forms because pupils were past the age of compulsory education. She could not think of any grounds on which Manshead could have legally removed Glenda Oduro from its roll.
Asked about this, Mr Parker said the guidance was "not that clear" for post-16 students.
Mrs Oduro, whose daughter is having to attend an extra foundation year at university to compensate for her lack of A-levels, is now being advised by solicitors on suing the school. "It worries me how many other schools have been doing this," she said. "And how long it has been going on for."
WHAT HAPPENS WHEN THE HEAT IS ON
Extract from letter written by Jim Parker, headteacher of Manshead School:
"This issue (Glenda Oduro) does raise a challenge that schools face. There is great pressure for schools to meet targets in all aspects of their work and I fully accept that schools should have targets against which their performance can be measured.
"Perhaps it is fair to say that in years gone by we would have allowed students like Glenda the chance to continue their studies. There, of course, would have been a strong possibility that they could have failed and in effect wasted two years at school, but other students may have succeeded.
"In marginal situations such as these, schools are encouraged (by the need to show that performance targets are met) to remove students from courses where failure is possible.
"I am not completely comfortable with this situation and would suggest that at Manshead we are very thorough in ensuring that all available interventions are made before a student is asked to leave the sixth- form.
"I know of other schools in the area where this is not necessarily the case and that students are asked to leave midway through courses that they have a reasonable chance of passing, but perhaps not at their target grade.
"I would like to make it clear that this scenario has not influenced our decision about Glenda, but I am worried that in the future it could."
Original headline: Heads resort to the ultimate penalty under league table pressure