A former police detective who investigated peadophilia allegations against Cyril Smith has said that if the MP had been taken to court, he would have exposed other high-profile offenders.
Mr Smith died in 2010 but Jack Tasker said the investigation into his alleged child abuse at Cambridge House care home was stalled because "other people were rather worried that if Cyril Smith went before a court, he would open his mouth".
Retired Det Sgt Jack Tasker, who served with Lancashire Police, carried out the third investigation in 1969, following two by the former Rochdale Borough force.
He told Sky News that senior officers repeatedly prevented him from properly investigating the case and that, if the former Rochdale MP had been prosecuted, the case could have led to the fall of the government at the time.
He said: "I think he was guilty and I think he should have faced trial.
"I think circumstances since have probably proved I was right, we were probably right."
He said that he had interviewed the boys and had believed what they had told him, adding: "They were interviewed separately and all had similar stories.
"You can tell a good witness, you can tell a shaky witness - it's part of your job to do so.
"I think Cyril would have been a shaky defendant."
Smith was accused of eight counts of sex abuse including six offences at a care home he set up in Rochdale but his family say he always denied the allegations.
Mr Tasker said that police had interviewed Mr Smith about the allegations and he had been "a very worried man", "sweating profusely".
He added: "After the interview, as he walked out the door, he said 'This will kill my mother'."
He said that he was stopped from investigating further after a visit to his office by people he assumed to be from Special Branch, who demanded his notes and other records from the investigation and told him to go no further with his inquiries.
He said: "We were under the impression then that they'd take the investigation over and were going to continue it. But I never heard any more about it."
Smith was the subject of allegations and investigations over decades during his career - first as a prominent local councillor in Rochdale and later as the town's Liberal MP - but he was never prosecuted.
