Secret hearings in ex-IRA informer Martin McGartland case
The Home Secretary has been granted the right by a judge to use secret court hearings to defend a damages claim brought by a former IRA informer.
Martin McGartland survived a shooting in Whitley Bay on Tyneside in 1999, and was given a new identity afterwards.
He is suing MI5 for breach of contract and negligence after the shooting.
The High Court judge said because of sensitive evidence in the case, "closed material proceedings" could be used in the interests of national security.
The ruling means Mr McGartland and his lawyers will not be able to hear parts of the case or to see "sensitive material".
Special advocates will be appointed to protect his interests.
The west Belfast man claims MI5 failed to provide care for post-traumatic stress disorder and access to disability benefits following the shooting, that left him unable to work.
His book about his experiences, 50 Dead Men Walking, was made into a film in 2008.
The judge said the case included a claim by Mr McGartland, together with his partner and carer Joanne Asher, that "their protection was mishandled".
Powers to hold secret hearings were introduced in July 2013 so that trials using Closed Material Proceedings (CMPs) can take place in civil courts without damaging national security.
Mr McGartland's lawyers have described such proceedings as "a serious aberration from the tradition of open justice".
They argued that his claim for damages for personal injury did not pose a risk to national security and would not expose any aspect of his undercover work as an IRA informer.
At a two-day hearing last month, government lawyers told the court that an assurance of "secrecy forever" lies at the heart of the relationship between the British Security Service and its agents.
The Home Secretary would "neither... confirm nor deny" (NCND) that he is a former agent.
His lawyers have complained that, because of this, there has been no response to Mr McGartland's specific allegations that the Security Service withdrew funding for medical treatment, was negligent in the changing of "handlers" and broke promises with regard to financial payments, the installation of a phone line and access to state benefits.
His legal team has argued that the NCND policy is unlawful as public statements naming Mr McGartland as an agent have already been made by official bodies including Crown authorities, the police, MPs and the Bloody Sunday Inquiry.
A barrister for the Home Secretary said in a written statement to the court: "An assurance of 'secrecy forever' lies at the heart of the relationship between the Security Service and its agents.
"The strict maintenance of the NCND principle is one of the most important means by which the Security Service makes good that assurance."
The judge said in his ruling that the "most difficult issue to be resolved will be how to deal with the detail of the claimant's case against his claimed handlers".
While in an ordinary claim for damages, disputes are resolved by a direct confrontation between the claimant and witnesses, the judge said if that was not possible, "a decision will have to be made as to whether or not such an issue can be justly determined at all, and if so, how".
He said the best way to deal with this was under the provision for closed material proceedings.