Police could have caught paedophile Ian Watkins and brought him to justice years earlier if they had adequately acted upon reports, an investigation has found.

The investigation by the Independent Police Complaints Commission found South Wales Police did not adequately action eight reports and three intelligence logs from six individuals concerning the activities of the former Lostprophets frontman between 2008 and 2012.

Watkins was jailed for 35 years in December 2013 after admitting a string of child sex offences.

IPCC commissioner for Wales, Jan Williams, said that the investigation raised "disturbing concerns" about the way the reports, which she said were subject to conscious or unconscious bias, had been handled.

The investigation was first launched in 2013 but there were reports made against Watkins as early as 2008.

Watkins' ex-girlfriend Joanne Mjadzelics first reported Watkins to the authorities in December 2008 and was video interviewed in March 2009 when she told officers she had a message on her mobile phone from Watkins about his wish to sexually abuse children.

The report says the phone was not examined "on the basis that her report was malicious".

The IPCC also found that several other people also reported information about Watkins' behaviour.

South Wales Police Assistant Chief Constable Jeremy Vaughan said it highlighted a number of failings "which the force entirely accepts and regrets".

"South Wales Police failed to listen and properly investigate information about Watkins' offending behaviour, for this we are truly sorry," he said.

In May a detective sergeant was cleared of misconduct over the handling of the case and no further action was taken against two detective constables.

An NSPCC Cymru Wales spokesman said the report's damning conclusions should be a "wake-up call" for all those involved.

"That a simple unchecked mobile phone could have helped to prevent further abuse by Watkins is unthinkable, and is just one cause for significant concern among this catalogue of basic failures," he said.

"While Watkins is now thankfully behind bars where he belongs, and improvements have already been made by South Wales Police, it's clear that very serious mistakes were made in handling multiple early allegations and this report's recommendations must be adopted swiftly."