A CRIMINAL investigation will be launched into allegations of a child abuse cover-up at a school linked to Sir Cyril Smith, it was revealed yesterday.

The Liberal Democrat politician, who died in 2010, is alleged to have used his status to sexually abuse young boys with impunity at Knowl View School in Rochdale.

Despite numerous previous allegations and past police investigations neither Sir Cyril nor other suspects were ever prosecuted.

A separate investigation is ongoing to identify people suspected of taking part in the alleged sexual abuse.

In a dramatic development police said yesterday they would probe alleged corruption by officers and local politicians as part of the alleged cover-up.

The inquiry was triggered by Rochdale Labour MP Simon Danczuk, who claimed in a recently published book that his predecessor Sir Cyril had raped a number of young boys at the residential school.

In Smile for the Camera: The Double Life of Cyril Smith, Mr Danczuk claims that police, spies and politicians helped to hide the historical child abuse carried out by Sir Cyril.

He was left free to abuse children as young as eight despite 144 complaints by victims, Mr Danczuk and co-author Matthew Baker said.

Greater Manchester Police (GMP) Assistant Chief Constable Ian Wiggett said yesterday: “Following the publication of MP Simon Danzcuk’s book ‘Smile for the Camera’, GMP conducted an assessment of the allegations contained within that book.

“As a result of the assessment, GMP decided that a criminal investigation was required.