A decision not to publish details of a tribunal involving a "Trojan Horse" school governor has been described as "exceptional".
Tahir Alam was chairman of governors at a Birmingham school embroiled in an alleged Muslim takeover plot.
He was issued with a ban in 2015 after he was found to have engaged in conduct undermining fundamental British values.
The ban was upheld at a tribunal in December, the details of which will not be made public.
Evidence was found of "co-ordinated, deliberate and sustained action to introduce an intolerant and aggressive Islamic ethos" into a few Birmingham schools, including Park View School in Alum Rock, where Mr Alam was chairman.
Although the tribunal following Mr Alam's ban appeal was held in public, the full ruling will not be published to protect the identities of some witnesses called by the Department for Education (DfE).
A spokesman for the Courts and Tribunals Judiciary said: "The final decision of the tribunal makes reference to those witnesses and sets out the evidence they gave, which the tribunal considers could lead to their being identified locally."
He said it was "exceptional that a public decision is not published on the tribunal's website".
Former Birmingham Liberal Democrat MP John Hemming said the decision not to make details of the tribunal public is "concerning" and that the hearing was an "issue of enormous public importance".