The will of the man alleged to have been Britain’s top agent inside the Provisional IRA is not to be made public, the high court has ruled in a legal first.

Ordering that the will of Freddie Scappaticci, who is suspected of being the mole known as Stakeknife, should not be open for public inspection as is usual, Sir Julian Flaux said it was the first time this had been done for a person who was not a member of the royal family.

Scappaticci, who was accused of torturing and murdering several victims while simultaneously running an IRA enforcement unit and working for the British state in the 1980s, died in hiding in April 2023 at the age of 77. He always denied being Stakeknife.

In his ruling, published on Monday, Flaux said a hearing to decide whether the will should be sealed was held in private on 21 July. The application was made by a man named Michael Johnson, who had said he was prepared to act as Scappaticci’s representative providing that the will was sealed.

Christopher Buckley, acting for Johnson, had told the court that making the will public would be “undesirable” and “inappropriate”. A barrister for the attorney general, who represents the public interest, had supported the application.

Flaux said: “There is nothing in the will, which is in fairly standard form, which could conceivably be of interest to the public or the media.”

He added that there was “the need to protect the applicant and those named in the will from the real risk of serious physical harm or even death because they might be thought to be guilty by association with the deceased”. This was demonstrated, the judge said, by “the real risk to his life and wellbeing which the deceased faced in his lifetime”.

He ordered the will should be sealed for 70 years.

A seven-year investigation into Stakeknife – alleged to have been the highest-ranking British intelligence agent in the IRA during the Troubles in Northern Ireland – published last year found that more lives were lost than saved because of his activities. Scappaticci, from west Belfast, was not named as the agent in the report.

Scappaticci, who went into hiding in England after his identity was revealed in 2003 by the media, failed in a legal attempt to force the government to publicly state that he was not Stakeknife.

He was linked to more than a dozen murders during his time as a senior member of the Provisional IRA’s ruthless internal security unit known as “the nutting squad”, which was tasked with identifying and killing security force informers.

Flaux said in his judgment: “The allegation that the deceased was working for the British government was particularly inflammatory in the Catholic community in Northern Ireland given that he was alleged to have been responsible within the IRA for dealing with individuals accused of spying on the IRA.”

In 2022, the Guardian revealed that senior government officials privately believed that the practice of keeping secret the wills of the royal family was legally questionable and warned ministers not to discuss it in parliament. The same year, the court of appeal dismissed a legal challenge by the Guardian to the exclusion of the media from a secret court hearing in which a judge banned the public from inspecting Prince Philip’s will.