Theresa May has been urged to extend the government's inquiry into child abuse to include Scotland and Northern Ireland.
The Home Affairs Select Committee said the review into allegations of high-profile paedophile rings should cover the whole of the UK, including claims of abuse at Kincora Boys' Home in Belfast in the 1970s, which MI5 are alleged to have been involved in covering up.
In a report, Theresa May has been urged let the inquiry investigate the allegations that senior politicians, military personnel, paramilitary figures and businessmen from Northern Ireland and the rest of the UK were involved in abuse at the care home and a subsequent cover-up.
In 1981, three staff members at Kincora were jailed after been found guilty of abusing 11 boys.
The report said: "We recommend that the scope of the inquiry be extended to include cases of abuse in Scotland and Northern Ireland, where there is reason to believe that material relevant to the case might be held by the UK government. This would include cases such as the Kincora Boys' Home."
It added the scope of the investigation would mean that it could not be "adequately considered in any way other than a Westminster government-led inquiry".
Northern Ireland programme director, Patrick Corrigan, said: "Nothing less than the inclusion of the Kincora home in this inquiry is liable to see the truth finally arrived at, and justice finally delivered.
"We hope that [May] will now heed the recommendation of the Home Affairs Committee that Kincora should be investigated alongside allegations of establishment involvement in child abuse rings elsewhere in the UK."
The Home Affair Select Committee also praised the appointment of its new chair, New Zealand judge Lowell Goddard, following the resignation of its previous two over their links to the establishment, but added it was "disappointed" details of her pay would not be revealed.
"This is not in line with the open and transparent approach we would expect in the course of a pre-appointment process," the committee said.
The inquiry was set up in July by the Home Secretary Theresa May over allegations of a high-profile Westminster paedophile ring in the 1980s.
However, it has already been severally criticised as a "farce" following the resignations of previous chairs Fiona Woolf and Baroness Butler-Sloss, as well as the victims feeling they have so far been "let down" by the lack of progress.