Thousands of teachers look set to go on strike this year as they continue their battle over pension reforms. But while many will willingly join the protest, staff at one school will be left with a very difficult, and very unusual, dilemma: their contract bans them from taking industrial action.
Now, ahead of the walk-outs, expected in November, their union has called on managers at Ashcroft Technology Academy in Wandsworth, south-west London - sponsored by controversial former Conservative party deputy chairman Lord Ashcroft - to scrap the clause.
Lord Ashcroft's school is a long way from a picture of union-management harmony. In addition to the no-strike clause, union negotiation rights are not recognised by school leaders or governors. Indeed, the local NUT alleges that teachers were told they could face disciplinary action if they took part in this summer's strikes. Unsurprisingly, no one took action.
They will be faced with the same quandary in the run-up to the new strikes later this year. Spencer Barnshaw, secretary of the Wandsworth branch of the NUT, is calling for his and other unions to be formally recognised by the school, and to discuss the no-strike clause with headteacher Marcus Barker.
But a letter he wrote in July requesting a meeting has gone unanswered. "I'm bemused by this lack of response. I think it's very rude to me and to my members in the school. It's a very strange position for him (Mr Barker) to take," Mr Barnshaw said.
The current wording of the clause, which says "the terms of this contract preclude you from taking any form of industrial action", date from the time the school was a city technology college in the 1990s. Despite the legal position of the school, Mr Barnshaw was allowed to speak to NUT members at the school before the summer pension strike, but he had no success getting them to ignore the controversial clause.
"The advice I was given by the union's legal department was that any such clause was not enforceable as it's against the law to prevent people taking industrial action. I believe a number of teachers did want to go on strike," he said. "My advice to them was to be sensible. I didn't want to call them out if it would put them at risk. But I do believe teachers should be able to withhold their labour.
"The pensions issue is not an argument with the school - it's an argument with the Government, who are not listening."
Employment lawyers suggest that the union's position is a strong one. Heather Bragg, a solicitor at Browne Jacobson, which specialises in employment law, said the clause was "extremely unusual" and should have "very little effect in practice".
"Taking union action is of itself a breach of contract. If you don't come into work to perform your duties because you are on strike, that is a breach of contract," she said. Employees are protected from disciplinary action by their employer if they are acting in official industrial action which is protected, or if it concerns a valid trade dispute and the union has complied with the balloting and notification requirements so as to qualify for immunity.
"Schools should be wary of relying on such clauses in isolation and should be mindful of the wider protection given to employees by the industrial relations rules before taking any disciplinary action during union action," Ms Bragg added.
A Department for Education spokesman said academies are free to set their own terms and conditions. "Decisions over contracts are a matter for individual teachers and their schools. Teachers that are transferred to academies under the Tupe regulations can retain their national terms and conditions."
But neither Mr Barker nor Lord Ashcroft responded to requests by TES for an interview. But with a wave of discontent on the way, there may be questions to answer.
Amanda Brown, head of the employment, conditions and rights department at the NUT, has persuaded governors of a school in Nottingham not to introduce a contract which gave teachers just 28 days' leave, to be taken during term time.
"They've now taken it off the table, and are going to reconsider, so our approach to this situation did have an impact," she said.
Ms Brown also fought proposals at another school which wanted to employ teachers on "zero hour" contracts. She believes the "flexibility" available to academies leads to "bad employment practice".