Pupils are being pressured into taking extra after-school classes by heads desperate to improve their English Baccalaureate scores, The TES has learnt.
The tactic is one of several panic measures being adopted by frightened schools trying to boost their performance on the new EBac league table measure, according to evidence gathered by the Association of School and College Leaders (ASCL).
To qualify for the EBac, pupils need at least grade C GCSEs or IGCSEs in English, two sciences, maths, history or geography and a language.
ASCL says pupils in some secondaries are being forced to give up their own time to attend extra sessions on history and geography GCSEs, both of which count towards the EBac.
The secondary leaders association has also found examples of pressure being put on Year 10 pupils who had been studying for two modern language GCSEs, to drop one and take geography instead.
ASCL deputy general secretary Martin Ward said: "It is not appropriate to be pushing people to be doing extra work like this, if it is not something they want to do, to improve the standing of the school.
"But we can understand why our members, particularly those in schools where results are below the Government's floor targets, feel under pressure to respond to this measure."
When the EBac was applied retrospectively to last year's results in the latest league tables, just 15.6 per cent of pupils achieved it.
Margaret Morrissey, from the Parents Outloud campaign group, said: "It is wrong for schools to do this and say, 'Because we have messed up we expect you to work after school and take lessons.' It isn't the students' fault."
A Department for Education spokesman said "The English baccalaureate is just one measure of attainment for schools.
"It's rightly down to individual heads and teachers to decide on how best to teach their pupils."
ASCL says schools have become used to the league table culture and "many" will change their curriculum from September in line with the EBac.
But the association says the changes are being made because schools fear Ofsted will judge them on the measure in future.
"We are advising members not to take precipitous action in reaction to the English Baccalaureate," Mr Ward said.
But he said some heads were also under pressure from governors and parents who believed universities would ask for the EBac, even though there was no evidence to support their concerns.
The Specialist Schools and Academies Trust is running courses to help schools "meet the challenge" of the EBac. But John Dunford, chair of the Whole Education campaign group, said they were a "sad compliance to a measure that ought to be opposed tooth and nail".
But when Michael Gove was asked by journalists at the conference whether he might change the EBac, the education secretary replied: "I love it the way it is, I'm not planning to change anything at the moment."
WHAT THE GRAMMAR DID - 'I don't care'
A high-performing girls' grammar has decided to ignore the English Baccalaureate and let pupils continue choosing subject combinations that would disqualify them from the measure.
At Fort Pitt Grammar, pupils sit GCSEs at the end of Year 10, with some pupils achieving as many as 14 good passes, and 99 per cent of pupils achieving the five A*-C, including English and maths, benchmark.
But only 17 per cent of girls at the school in Chatham, Kent, achieved an English Baccalaureate last year.
While other schools are changing the curriculum to do better on the new league table measure, last week Fort Pitt governors decided pupils should still be able to opt out of history and geography or a language if they wanted to, even though they would rule themselves out of an EBac.
Head Julia Bell said she was "thrilled" by the decision. "I don't care where we are on the EBac league tables," she said.
"I like breadth and I think we should keep breadth. But (EBac) choices are too narrow in the humanities and Biblical Hebrew (which qualifies in the EBac) - come on, what's all that about?
"I wonder if we are not repeating a curriculum for 20 or 30 years ago (through the EBac) rather than a curriculum for the 21st century." William Stewart
OUT AND PROUD - Union campaign
ASCL is part of the A Better Baccalaureate campaign calling for the EBac to be replaced with a broader measure of achievement. The association distributed "I failed the English Bac!" badges at its conference last weekend where general secretary Brian Lightman warned that any subject not included in the EBac would be "automatically" devalued.