A teachers' union is threatening to take the government to court over changes to pension plans.
The NASUWT has issued a further legal challenge to the government in relation to its plans for changes to the teachers' pension scheme.
The union insists government plans for pension reform should not proceed without a valuation of the scheme. A valuation would reveal whether there was a problem with the viability and sustainability of the scheme and, if there was, the scale of the problem.
The NASUWT contends that the government has a statutory responsibility to conduct a valuation of the teachers' pension scheme. The last valuation was conducted in 2006 and the regulations require a further valuation in a period not exceeding five years.
"The government has ignored our repeated requests to produce a valuation of the scheme" said Chris Keates, NASUWT general secretary.
"It is simply unacceptable and irresponsible for a government to embark on changes which will have such a profound adverse impact on the financial future of teachers and their families without having evidence to demonstrate that a problem even exists.
"Not only is the government failing to meet its obligations to teachers, it is failing in its duty to act in the interests of the public.
"It is, however, probably safe to assume that if a valuation would have provided evidence to support the government's changes, it would have produced it.
"The failure to provide the valuation has deeply angered teachers".
The NASUWT has served a pre-action letter on the Government Actuary's Department, the education secretary and HM Treasury.