Chancellor George Osborne told BBC Radio 4's Today programme that the investigation into the disappearance of files handed to the Government that allegedly related to claims of organised child sex abuse at Westminster in the 1980s would be "independent and authoritative".
"In my view it needs to go as far as it needs to go to find out what happened. That is the only thing that matters here. We need to get to the truth." Osborne said.
The Baroness says she did not consider the "difficulties" caused by her background and family connections to the child sex abuse inquiry.
Questions have been raised of former High Court judge Baroness Butler-Sloss since her appointment last week.
22 police officers are now assigned to Operation Fernbridge - the probe into claims of a Westminster cover-up of sex child abuse.