The head of one of the country's biggest teaching unions has accused the education secretary of spending £21m on consultants while he cuts school budgets.

Christine Blower, general secretary of the National Union of Teachers, said her union had analysed the Department for Education's spending based on figures published on its website.

Blower told her union's annual conference that the analysis showed Michael Gove had paid £21m to five private firms between last April and February. The union claims a further almost £5m was awarded to three other private companies.

Blower said she feared much of the £21m had been taken from state schools and used for free schools. Free schools are one of the coalition's flagship education reforms and are founded by parents, teachers, charities and companies. They operate out of local authority control.

A Department for Education spokesman said spending on consultants had been "slashed" under the coalition government. In 2009-10, more than £74m had been spent on consultants, he said. But, when figures are published for the last financial year, they will show spending on consultancy has been "significantly reduced", he added.