"It is now clear that the prime minister must guarantee that former police and intelligence officers who wish to help the IPCC with their inquiries will have the threat of the Official Secrets Act lifted."
He said it was the "duty of all former police officers, intelligence officers and civil servants who have knowledge of a cover-up" to come forward.
"There has to be a more formal response from government which says that former police officers who co-operate, give evidence and share their knowledge of what went on with regard to this alleged cover-up should not be disciplined in any way, with regard to the Official Secrets Act or in any other way," he said.
In a statement, the Home Office said: "The home secretary has given clear assurances that the Official Secrets Act is not a bar to giving evidence to either the independent panel inquiry into child sexual abuse or ongoing police investigations."
It said police officers "can be authorised" to disclose information which would be covered by the Official Secrets Act "so long as it is disclosed in an appropriate way".
BBC home affairs correspondent Tom Symonds said there "is definitely a view that the government should be clearer about saying there is absolute immunity for police officers… whistleblowing in this sort of situation".
"The question arises, for example, what if a retired police officer speaks to a journalist? Is he at risk of being prosecuted then?" he said.
[link to m.bbc.co.uk
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