04/08/2015 08:48 BST | Updated 04/08/2016 06:59 BST

We Need to Ensure the State Never Allows the Powerful to Evade Justice Again

Since 2012 I have referred two allegations made against former prime minister Edward Heath to the police. It is for the police to investigate and we need make sure they are given the space and time to do that.

I would like to see the creation of a new national police unit to deal with child sex abuse cases. Only then will the chances of intelligence failures be minimised.

But it was alarming to learn on Monday that Wiltshire police is to be investigated by the Independent Police Complaints Commission over allegations it dropped a criminal case in the 1990s because the suspect threatened to go public with allegations about Heath. That should concern us all. It is not the first time agencies of the state have been accused of failing to investigate claims made against members of Parliament or suppressing criminal inquiries into MPs.

The survivors of child abuse serve a double sentence for the crimes committed against them; the pain of the original abuse is amplified by the terrible knowledge that when they had the courage to speak out no-one listened and no-one believed them.

All too often it has been reporters who have carried out the painstaking investigatory work the police failed to do.

The brilliant BBC journalist Liz MacKean obtained the Special Branch file that laid bare buried accusations and abandoned investigations into Cyril Smith, the former Liberal Democrat MP for Rochdale and serial child abuser. They helped suppress an inquiry into the late MP.

The veteran reporter Tom Mangold broadcast an interview with the man who claimed to have been hired by people close to the Liberal Party leader Jeremy Thorpe to kill his former lover Norman Scott in the 1970s.

"He leveled the gun at me again, it still must have been jammed and he just said 'I'll get you.'" said Norman Scott, describing how his would be assassin's gun jammed at the crucial moment.

Dennis Meighan confessed he was hired to kill Scott and supplied a gun to an accomplice who pulled it on Scott after killing his dog, Rinka, on Exmoor.

Meighan says this information was contained in his statement to the police. But he told Mangold he was later given a second pre-prepared statement by the police that removed all mention of Thorpe - thus ensuring Meighan was not be a witness in the Liberal leader's 1979 conspiracy to murder trial at the Old Bailey. Thorpe was cleared of all wrongdoing.

You can hear Mangold's interview with Meighan in its entirety here.

There are many more examples. Former Detective Chief Inspector Clive Driscoll has claimed that he was removed from a child abuse investigation in Lambeth when it became known one of his suspects was a Labour MP.

Since I first raised the issue of organised child abuse in Parliament in October 2012, I have heard numerous allegations of police inquiries being abruptly closed down for no apparent reason.

It's vital that the Independent Inquiry into Child Sexual Abuse chaired by Judge Lowell Goddard establishes how this was allowed to happen.

Was it a conspiracy by powerful people at the heart of the state or was it, as Tom Mangold wrote about the Jeremy Thorpe case, "a conspiracy without conspirators, a silent conspiracy based on assumption, custom and instinct. That was how things used to work."

Whatever the reason for past failures, survivors of child sexual abuse deserve to know what happened. Many perpetrators are now dead but we owe it to their survivors to uncover the truth. And we need to ensure the state never allows the powerful to evade justice again.