A former army officer has been assured he will not be held in breach of the Official Secrets Act if he gives evidence about what went on at Kincora Boys’ Home.
One former resident of Kincora, Gary Hoy, is taking legal action in a bid to have the scandal examined by a wider Westminster inquiry.
Senior politicians, businessmen and high-level British state agents are alleged to have been complicit in the molestation and prostitution of vulnerable boys at the east Belfast home throughout the 1970s.
Calls for full scrutiny have grown since three senior staff at Kincora were jailed in 1981 for abusing children in their care.
Lawyers representing Mr Hoy, claim MI5 shielded and blackmailed perpetrators as part of a cover-up.