Murderer Jeremy Bamber has lost a bid to bring a legal challenge over a refusal by the Prison Service to downgrade him from maximum security.

The 59-year-old is serving life after being found guilty of murdering his adoptive parents, Nevill and June, both 61, his sister, Sheila Caffell, 26, and her six-year-old twins, Daniel and Nicholas, at White House Farm, near the village of Tolleshunt D’Arcy in Essex, in August 1985.

He has always protested his innocence and claims that Ms Caffell, who suffered from schizophrenia, shot her family before turning the gun on herself.

Bamber sought permission for a High Court challenge over a decision taken in March by the director of the long-term and high security estate – part of the Prison and Probation Service – not to downgrade him from a Category A inmate, or to direct that an oral hearing on the issue take place.

Category A prisoners are considered the most dangerous to the public and held in maximum security conditions.

At a remote hearing in October, lawyers for Bamber asked Mr Justice Julian Knowles to give the go-ahead for a full hearing of Bamber’s claim, arguing that the decision was “unreasonable”.

In a ruling on Friday, the senior judge refused Bamber permission to bring the challenge.

In his judgment, Mr Justice Julian Knowles said: “I have concluded that permission must be refused on the basis that neither of the grounds of challenge advanced on behalf of the claimant is arguable.”

In written documents before the court, Bamber’s barrister, Matthew Stanbury, had argued that an independent psychologist’s report, commissioned by Bamber’s solicitors, had concluded he had met the test for downgrading a Category A prisoner and that these conditions were “no longer necessary” for managing him.

He argued that the decision not to downgrade Bamber from Category A was “unreasonable” as it “substantially misrepresented” the opinion given by the independent psychologist.

It was argued that the director’s decision wrongly stated that the psychologist had concluded it was “impossible” to assess Bamber’s risk, when she had actually concluded that, while it was “difficult” to assess the risk, it was not impossible.

Mr Stanbury also said that “fairness required an oral hearing” over whether Bamber should be downgraded, for reasons including the fact that he “has served 35 years without ever having an oral hearing, and the passage of time means that a risk assessment is more difficult without a face-to-face assessment”.

The Ministry of Justice opposed Bamber’s action.

In his ruling, Mr Justice Julian Knowles said he agreed that the director was “wrong” to say the psychologist “had concluded that an assessment of risk was ‘impossible’”.

“She did not say that, and her report cannot reasonably be read to have reached that conclusion,” the judgment says.

“She expressed her conclusion that such an assessment was possible, and she made one. Whether or not this was just lazy language on the director’s part, it was an error.”

But the judge added: “Equally, however, when the director’s decision is read as a whole it is plain that he had the right question in mind and that the reasons he gave for refusing to recategorize the claimant were ones which were reasonably open to him on the evidence.”

He also said he was “entirely satisfied” that Bamber had had “a fair opportunity to present his case on why he ought to be re-categorised even without an oral hearing”.

The challenge is the latest action in Bamber’s long-running battle to clear his name.

He had an appeal against his convictions dismissed by the Court of Appeal in 2002, and also had a High Court challenge to the Criminal Cases Review Commission’s (CCRC) refusal to refer his case for another appeal rejected in 2012.

Bamber is in the process of pursuing a fresh application to the CCRC.