Image copyright Owen Humphreys Image caption Sixth-form colleges say cuts have hit them harder than other educational institutions

Strike plans by sixth-form college teachers are "unlawful", according to a government challenge in the High Court.

Members of the National Union of Teachers in England plan a one-day strike on Tuesday over "inadequate funding" in sixth-form colleges.

Some 86% of 1,689 sixth-form college members who voted, in a 44% turnout, backed the strike call.

The government is seeking an injunction to stop the strike, arguing it is politically motivated.

In last month's ballot, members were asked: "In order to persuade the secretary of state for education to increase presently inadequate funding levels which cause detrimental changes to terms and conditions within the sixth-form college sector, are you prepared to take a day's strike action?"

In the vote, 1,453 were for the strike and 235 against, with one spoiled paper.

'Difficult decisions'

A Department for Education (DfE) spokesman said: "The NUT is seeking to disrupt the education of thousands of students through what we believe to be an unlawful dispute, based on political grounds and not a trade dispute about the terms and conditions of its members."

Sixth-form colleges have long argued for more money, saying they have experienced deeper budget cuts than any other group of educational institutions.

Changes announced in November's Spending Review went some way towards redressing this, the government argues.

"We recognise the importance of investing in education which is why, thanks to the difficult decisions we have taken elsewhere, we have been able to protect core 16-to-19 funding," said the DfE pokesman.

"At the same time we have ended the unfair difference between post-16 schools and colleges by funding them per student to ensure that all young people leave education with the skills they need to thrive in modern Britain."

But the NUT calls the legal challenge "cynical" and says it intends to "robustly defend its right to strike to protect jobs and conditions".

'Vital service'

Deputy general secretary Kevin Courtney said: "We regret that the government has chosen this route rather than seeking to resolve the dispute through negotiations about adequate funding for the sector, which could protect teachers' conditions of service and students' conditions of learning.

"Sixth-form colleges provide a vital service that is in danger of all but disappearing if government does not listen and reverse and remedy the severe funding crisis in colleges."

Image caption Sixth-form colleges have long complained about poor funding

Sixth Form Colleges Association chief executive David Igoe told the BBC there were about 3,000 NUT members in sixth forms out of a total teaching staff of about 8,000.

Describing the planned strike as "ill-timed and ill-judged", he said it was unlikely any college would have to close if the industrial action went ahead.

He said the action was at a bad time for students preparing for exams, would risk damaging the sector's reputation with parents and could undermine the "good result" in the Spending Review.