An Ofsted inspector with 20 years of service was sacked after conducting an independent review which concluded that a school at the centre of a rebrokering battle was making “good progress”.

The dismissal highlights a “grey area” within the watchdog’s rules for its part-time consultants and the work they do outside their duties with the inspectorate.

In September, the Department for Education published a termination notice for Landau Forte Academy Moorhead, in Derbyshire. The DfE said there was no “formal evidence” that the Landau Forte Charitable Trust was “providing has had, or is having, any impact on the outcomes of pupils”.

The trust said it was appealing against the decision and commissioned an independent review from an Ofsted inspector who works as a school improvement consultant.

The inspector, who wishes to remain anonymous, produced the report on October 14, but two days later saw his employment with the inspectorate terminated for engaging in activities that “materially breached” his contract.

The report was said to have found the school was making “good progress” from its special measures judgment. It has not been published, however, so it is unclear how Ofsted came by it.

In the reasons given for the termination, Schools Week understands that Ofsted pointed out that inspectors must not use the inspectorate’s name – except when working for the watchdog.

It added that Ofsted inspectors must never represent themselves as an inspector for purposes of commercial gain, nor use Ofsted information for purposes other than with Ofsted. Inspectors must also not disclose that Ofsted is a client or use Ofsted’s name or brand for promotion.

However, the inspector claims to have breached none of these rules. He did not use the watchdog’s name when promoting his consultancy work, only mentioning that he was a schools inspector who previously worked as an HMI, and only used Ofsted’s name on his CV.

A spokesperson said Ofsted did not comment on individual cases. Its conflict of interest policy states that inspectors must declare “previous, present, or future consultancy work” with schools and trusts – yet it does not forbid them from doing such work.

The inspector told Schools Week that they regularly updated their conflict of interests to record which trusts they were working with to ensure they were not sent there on Ofsted business. They had never previously had a problem or been told to stop.

The role of Ofsted inspector (OI) differs from that of a Her Majesty’s Inspector (HMI) – which is a full-time position. OIs are mostly seconded from schools and colleges, and some also work in consultancy roles.

Schools Week found numerous examples online of consultants who highlighted Ofsted experience when offering their services. Clive Davies, of education support and consultancy firm Focus Education, said there was “undoubtedly a grey area… It would be very foolhardy of anybody to believe the schools’ agenda isn’t driven by what Ofsted is going to think of them.

“Therefore, this is where the grey area comes into it. If we didn’t have knowledge of the framework from Ofsted, real knowledge, we would be found wanting in our ability to support schools as well as they would like us to.”

Ofsted has got tough on inspectors doing other work. It banned them from running “mocksteds” in schools in 2015, with inspectors said to be charging up to £600 a day to help heads prepare for a visit from the inspectorate.

But schools commissioning independent reviews seems to be quite common. Khalsa Academies Trust, for instance, commissioned a governance review by the Confederation of School Trusts earlier this year as a condition of a financial notice to improve.

The case also throws up potential difficulties for organisations such as Challenge Partners, a charity that runs peer review programmes to inform school improvement.

Its quality assurance review is described as being led by “an Ofsted-experienced lead reviewer, supported by senior leaders and headteachers from other schools in the network”.

The charity did not respond to a request for comment.

Davies said that, while some of the firm’s consultants have Ofsted experience, they have cut ties with the watchdog as navigating the grey area was potentially too troublesome.

Emails sent to OIs, and seen by Schools Week, warn against undertaking any form of “mock” visit or Ofsted training and revealed that a few OI contracts had been terminated due to such breaches since “interim visits” began in September.

Duncan Woodhead, of the FDA Union which represents inspectors, said he would have “serious concerns if merely stating on a CV that you were previously an HMI would cause Ofsted to terminate an OI contract”.

When asked about the review, Landau Forte would only say that it was “explicitly not a ‘mocksted’, nor did it award any type of grade”. It refused to share the report.

Moorhead school has twice been judged “inadequate”. Carol Gray, interim regional schools commissioner for the East Midlands and Humber, has said there is a “very real risk that performance will not improve and children will not receive the education they deserve”.

Clarification: This article was amended to state the review commissioned by Khalsa Academies Trust followed a financial notice to improve.