According to Mr Robinson a copy of the report from Lancashire Police was passed to Special Branch, which dealt with national security and intelligence.
Mr Robinson, who had a previous interest in the case, said he read Sir Cyril’s file. He said: “I looked through Sir Cyril’s file which was kept in a safe in our office.
“It was thick full of statements from young boys alleging abuse. It had been prepared for prosecution.
“Written across the top of it were the words: ‘No further action, not in the public interest. DPP [Director of Public Prosecutions].’
“Shortly after taking it out I was called by an MI5 officer. They asked if I had the file on Mr Cyril Smith, and said: ‘Please have this sent down to London.”
On Tuesday Simon Danczuk, the Labour MP for Smith’s former constituency in Rochdale, described him as a “29 stone bully” who “imposed himself” on his victims whom he “humiliated and terrified”.
Mr Danczuk said some alleged victims had only now come forward in the wake of the Jimmy Savile scandal and it was time to find out “why was this allowed to happen”.
Smith’s brother, Norman, said he was “staggered” the MP was blackening the name of Sir Cyril, who died in 2010, adding that the police found at the time that there was no case to answer.
Barry Fitton, a former resident of the Cambridge House hostel in Rochdale, told the website politicshome.com that when he was 15 Smith would make him strip, smacked his bare bottom and then stroked his buttocks.
On another occasion, Smith subjected him to a “medical” that involved him stroking his thighs and testicles.
Another former resident, Eddie Shorrock, who was 17, said Smith, who founded the hostel and had keys to its premises, also gave him a “medical” whenever he took time off work.
Mr Danczuk said a third victim, who wished to remain anonymous, had contacted him today to describe the “abuse meted out by Sir Cyril”.
Rumours about child abuse dogged Smith for much of his life, and appeared in a local magazine and in Private Eye in 1979.
Mr Danczuk, referring to the recent Rochdale grooming scandal, said:
“Attempts to suppress the truth are not new in Rochdale.
“Sir Cyril Smith was a political giant in Rochdale but his career was continually dogged by allegations that he had abused boys…these allegations must be properly investigated and the seriousness of the victims’ complaints must be acknowleged.
“Young boys were humiliated, terrified and reduced to quivering wrecks by this 29-stone bully imposing himself on them.”
Mr Danczuk made the comments during a debate on child sexual exploitation.
A CPS spokesperson said: “We cannot confirm at this stage whether the CPS, or any previous DPP’s office, received a file of evidence in relation to Cyril Smith, but we are currently doing what we can to double check available records.”
A Lancashire Constabulary spokesman said they were not planning to investigate the matter as there are no current allegations pending.
He added: “We believe there was an investigation in the late 1960s but as no records are now held it cannot be ascertained whether a file was passed to the Director of Public Prosecutions.
“These historic allegations date back more than 40 years and to a time when Rochdale was within the Lancashire Constabulary area.
“While we take matters such as this extremely seriously we have not received any further allegations and at this time there is no ongoing investigation in relation to this matter.”