"These figures make clear that the free school, UTC and studio school programmes were ill-thought policies which, in many cases, resulted in an appalling waste of significant sums of money," Kevin Courtney said, as quoted in the union's statement.
Courtney said that the government's priorities for education were wrong.
"To put the significance of this wasted money in context, £138.5 million would: provide 39% of the funding needed to ensure that no school loses funding in cash terms as a result of the introduction of the Government’s proposed new National Funding Formula; or restore 14% of the cuts to real-terms value of per-pupil funding since the 2015 election; or provide £6,586 for every school in England; or fund the employment of 3,680 teachers for a year," the union's general secretary said.
Courtney expressed concern over the authorities' apparent intent to press on with the formats that proved unsuccessful and urged the government to give up on failed programs.