A young beat bobby was threatened with the Official Secrets Act after he found Cyril Smith in the home of a known sex offender with two teenage boys, he has told the M.E.N.

He alleges he was summoned to a meeting with a senior officer and mentoring officer and told ‘in no uncertain terms’ to say nothing about it.

And the retired officer also revealed just four weeks ago he received an anonymous call from a man who said: “There may be an investigation – keep your mouth shut.”

GMP has told the M.E.N. it is treating the claims as “concerning “ and vow they “will be treated seriously”. They will be part of Operation Clifton - an on-going investigation into how historic reports of child sex abuse were allegedly covered up.

The former officer told how he called at a house in Stockport in 1988 after a complaint that the occupier had been committing a lewd act in his window in front of a newspaper boy.

When he arrived he said the then Rochdale MP Smith was there, together with a police officer in civilian clothes and two teenage boys – one a runaway from a children’s home.

The officer said: “I had been in the force about six months. The occupier was about 70 and seemed an old grandad type. In the house was Cyril Smith and a police sergeant in civilian clothes. The officer identified himself and showed his warrant card, saying he was there ‘on other business’.

“There seemed to be a party going on, with two young lads there. Smith and the officer left. The boys, aged about 14 to 15, were drunk.

“One was missing from a children’s home. I called for a van and took him back. The other lad walked off. The old man was arrested and I took him to the main police station in Stockport.”

He said at the station he discovered that the pensioner had a record dating back to the 60s for sex offences and had spent half his life behind bars.

He was just given a caution for the latest offence – a decision the officer ‘found very strange’.

The next day he was called to a meeting by a senior officer and his mentoring officer, Don Mackintosh, who would later be jailed for being a paedophile and abusing young boys over more than a decade.

He recalled: “I was told I would break the Official Secrets Act if I told anyone. In no uncertain terms I was told to say nothing at all.

“Mackintosh was my mentoring officer – in charge of all young bobbies. I was told don’t say anything - it’s all in hand. CID will deal with it. They knew Smith was there and knew who he was.”

Two months later for saying nothing and ‘doing a good job’ he was rewarded with a police driving course.

He said: “Normally you never got on a driving course when you were on probation.”

As reported in the M.E.N. an investigation by the Independent Police Complaints Commission will include allegations that Smith’s abuse of children in London was covered up by Scotland Yard.

The officer said: “When I entered the house in Stockport, Smith showed no real signs of concern. Normally if a bobby knocks on your door you go into panic.

“What was said to me at the meeting is word for word what was said to the officers in London. It fits in with everything else that has been said.”

Assistant Chief Constable Ian Wiggett said: “These fresh allegations will now be examined by Operation Clifton, a criminal investigation launched by GMP in July 2014 into how previous reports of child sexual abuse were handled or allegedly covered up.

“Clearly there are people who are willing to talk to the media but have not yet spoken to police. We have spoken to the M.E.N. about these latest allegations and we have asked them to pass our details to their source with the reassurance we will treat the information they give us in the upmost confidence.

“These allegations are concerning and will be treated seriously. GMP has allotted considerable resources to Operation Clifton, and we are committed to investigate all the allegations as best we can.

"As part of Operation Clifton we have already interviewed a large number of people and still have numerous enquiries to undertake. we are speaking to everyone no matter what status they have held or still hold to get to the truth.

"It is also important to note that the inquiry has the benefit of an independent scrutiny group, who will provide a high degree of scrutiny throughout the investigation.

"As these new allegations relate to misconduct by police officers, even though officers may have since retired, the matters have been referred to the Independent Police Complaints Commission.

“I urge anyone with information to call the incident room on 0161 856 0310.”

Officer claims disgraced sergeant also assaulted two cadets

The officer has also claimed that paedophile policeman Don Mackintosh assaulted two force cadets.

He also alleged that Mackintosh was tipped off about his impending arrest for a string of sex assaults and was able to resign and keep his police pension.

Mackintosh was jailed for nine years in 1994 after admitting a decade of abuse against young boys.

As reported in the M.E.N. he was found hanged in October last year at his home in Stalybridge.

The 71-year-old former sergeant was facing fresh child sex allegations dating back to the 1970s and a trial had been scheduled for May.

On his original arrest he opted to retire and took a £52,000 golden handshake plus £11,000 a year pension.

The officer claimed: “He was warned about three weeks before his arrest to resign in order for him to be paid his pension in full.

“I thought it was disgraceful at the time. Don Mackintosh was a very popular officer. He was looked after. They rallied round him and allowed him to resign.”

The officer said he was spoken to by a detective inspector just before Mackintosh resigned.

He added: “A week later I got a visit from the Y department (professional standards branch) who wanted to question me about Mackintosh’s habits and an allegation he had interfered with a couple of police cadets. I said he had never molested me and the officer said ‘that’s the answer we want you to say’.

“I know two bobbies that were abused by him. They told me that when they were cadets that he assaulted them, yet he was never charged.”