The organisation set up to help groups start their own "free schools" should be stripped of its charitable status because its aims are too political, a major union conference will hear.
A motion tabled for the annual meeting of the TUC says the New Schools Network, which recently received #163;500,000 from the Government to promote the controversial policy, is too "overtly political" to be a charity.
The network, which describes itself as "independent", was set up over a year ago by Rachel Wolf, a former aide to Education Secretary Michael Gove, and has since been charged with overseeing applications for new schools from parents' and teachers' groups.
Another former special adviser to Mr Gove, Dominic Cummings, is also reported to be helping out on a voluntary basis.
Mystery surrounds the organisation's other sources of funding because it has refused to reveal the names of anonymous donors.
Campaigner for comprehensive schools Fiona Millar has already asked whether the charity will be able to give objective advice to parents, as organisations with a "vested drive" to remove education from local authorities are well represented among its advisers and trustees.
Sir Bruce Liddington, director of academy operator E-ACT, and Amanda Spielman, head of research and development at academy operator Ark Schools, sit on the board.
There are also concerns over the way in which the Government money was awarded to the charity. A Freedom of Information Act request asking whether the Government knew if any of the charity's funders had a commercial interest in free schools has gone unanswered.
Mary Bousted, general secretary of the Association of Teachers and Lecturers, whose union put forward the motion to the TUC, said: "They have been given half a million pounds by this Government to go around brokering free schools and it's quite obvious that this organisation is absolutely hand-in-glove with the Conservative party.
"Michael Gove and Rachel Wolf say the schools will be set up and run by teachers and parents, but what will happen is private companies will come in and make a profit."
Hank Roberts, an anti-academies campaigner, said it was an "outrageous situation" that a charity was allowed to be engaged in an "overtly political agenda".
Ms Wolf responded to the accusations by saying the charity was non-partisan and dedicated to helping children, particularly in poorer areas, to get a good school.
"It is a shame that some union leaderships seem unable to see educational improvement outside the prism of party politics," she said.
A spokesman for the Department for Education said: "New Schools Network is a charity like numerous others that the Department has relationships with. Any grants will be made in accordance with the standard rules."
700 - Expressions of interest in setting up schools made by June 2010
50% - Proportion of enquiries said to be from teachers
62 - Formal applications received
220,000 - Tory pre-election proposal of free schools to create over ten years.