Northamptonshire Police deny claims that former MP Cyril Smith was released after he was allegedly found with indecent images of children

Mr Smith was stopped by police while driving on the M1 in the 1980s when, it is alleged, indecent images of children were found in the boot of his car.

But in a book published this year, Labour MP Simon Danczuk states that officers allowed Mr Smith to continue his journey after making a telephone call to a third party in London.

Following criticism, the police have said that they have investigated the claim by interviewing not only Mr Danczuk, but members of staff who would have dealt with the case at the time.

Assistant Chief Constable Ivan Balhatchet said: “On behalf of Northamptonshire Police, I would like to reassure everyone there is complete transparency in the investigation into the allegations that Cyril Smith was stopped in Northamptonshire with indecent images of children in the early 1980s.

“A thorough and far-reaching investigation by the force’s cold case team is continuing and we have been working with other forces involved in the wider investigation.

“We have spoken to the author of the book where the original claims were made and he and his co-author, and another journalist who has investigated Smith, have all been interviewed as witnesses.

“A large number of former and serving officers, who were serving in various ranks at the time of the alleged incident, and a member of police staff, have also been interviewed, and none can support the events alleged in Mr Danczuk’s book. “We have also made inquiries with the Crown Prosecution Service (CPS) and no archive CPS materials relating to the specific allegations can be found.”

Police have confirmed that investigations into the allegations towards Mr Smith, who died in 2010, are still ongoing.

Asst Chief Con Balhatchet said: “As yet, no witnesses have been found in relation to these allegations.

“However, we are continuing to search our archives and have widened the scope of our witness search, which includes contacting the people who were chief officers at the time.

“The investigation will continue until all reasonable lines of inquiry have been exhausted and the public can be assured that further updates will be provided as soon as we are in a position to do so.”