Prime Minister Theresa May has given assurances to an MP that Government papers relating to the late Cyril Smith will not be withheld.
Former shadow minister Lisa Nandy told the Commons that she had received a letter from the Prime Minister which stated the "work of the security services will not prevent information being shared".
The letter prompted Ms Nandy to ask Home Secretary Amber Rudd whether she had been wrong to assert last month that some papers would be held back "under national security".
The Wigan MP said: "Last month in this House the Home Secretary told me that some papers would be withheld from the Cyril Smith inquiry for national security reasons.
"This week the Prime Minister has written to me to say we are clear that the work of the security services will not prevent information being shared with other such inquires.
"So can she can confirm to the survivors of Cyril Smith (pictured) who have waited for justice for decades that she was wrong and that the Prime Minister is right?"
Ms Rudd replied: "Well I am happy to confirm the Prime Minister is always right and I will certainly look carefully at the letter that she has received to ensure that we comply with it."
Smith, who was an MP for Rochdale between 1972 and 1992, is accused of sexually abusing a number of boys.
The Independent Inquiry into Child Sexual Abuse has heard evidence of the abuse and will publish its findings next year.
In her letter to Ms Nandy, the Prime Minister said: "As with the Government's co-operation with the investigation into allegations of abuse at Kincora Boys' Home in the 1970s, we are clear that the work of the security services will not prevent information being shared with other such inquires.
"Material relating to the allegations of abuse at Kincora Boys' Home was disclosed to the Historical Institutional Abuse Inquiry team in full.
"To assist with disclosure, a memorandum of understanding was established between the inquiry team, government departments and security services with regards to viewing and securing potentially relevant material.
"If material was identified as relevant to the inquiry, government department and security services would consider it for public disclosure, in line with UK Government disclosure obligations."
Copyright (c) Press Association Ltd. 2017, All Rights Reserved. Picture (c) John Stillwell / PA Wire.