A high-profile academy trust has told the High Court a “glaringly perverse” unpublished Ofsted report should be quashed.

Durand Academy, which has two sites in south London and boarding provision in West Sussex, is disputing the findings of inspectors who said it should be put in special measures following an inspection in November and December 2016.

Last month, the Department for Education announced it would terminate the academy trust’s funding agreement next year, following concerns about its complex governance arrangements.

A draft of the Ofsted report briefly appeared on the inspectorate’s website in February, but the school has since obtained an injunction to prevent its publication.

Speaking at the High Court today, lawyer Gerard Clarke, representing Durand, said the judgement was unreasonable, “accentuating the negative and eliminating the positive”.

He said: “I can see how Ofsted could have brought a judgement of ‘requires improvement’, but the court ought to find itself surprised that Ofsted has been able, on the basis of the materials it saw and the inspection, that it could go as far as ‘inadequate’.”

He questioned how Durand could have suffered a “cataclysmic fall” from “good” to “special measures” in three years, and said that while its pupils “do not do all that terribly well” at key stage 1, the school delivers a “transformative turnaround effect” at key stage 2.

He also raised concerns that the report had a disproportionate focus on the boarding provision, which he said has about 70 pupils, rather than the main school which has more than 1,000, which he said was “the boarding school tail wagging the school dog”.

An attempt by the academy trust to ban the publication of its name was thrown out at the start of the morning’s proceedings.

Deok Joo Rhee, representing Ofsted, told the court the school had expanded to include early years and boarding provision in recent years, and added: “It is only to be expected that there’s some variation in what inspectors found over the years, given that history.”

Ms Rhee denied suggestions that the change in Ofsted judgements implied the school had gone off a “cliff edge”, and told the court that previous reports had highlighted areas of concern.

She said: “The school has had plenty of notice that it required improvement but it regrettably failed to bring these about.”

She added that Ofsted complied with all the relevant laws and regulations when reaching its verdicts on Durand, and it was “simply not an answer” to say the majority of the criticisms applied to the boarding school.

Mr Clarke also highlighted what he called Ofsted’s “Alice in Wonderland” appeals process.

He cited the inspectorate’s guidance about making a formal complaint, which says that if the complaint is about the school being judged to have serious weakness or to require special measures, the judgement would not be reconsidered “because all such judgements are subject to extended quality assurance procedures”.

He added: “We say that there is an element of Alice in Wonderland world here. They say there’s no need for a complaint process because ‘we will always definitely get it right first time’.

“‘We have decided that when we are extra careful we will get it right first time. We accept when we are less careful or strict we might mess it up and you can have a proper review’.”

Ms Rhee described the complaints process as “fair and rational”, and added: “There are rigorous quality assurance processes in place that make sure that errors are picked up and addressed”.

The hearing continues tomorrow.