One of the least satisfactory features of New Zealand's criminal justice system is the use of one prison inmate's testimony against another, usually in the form of incriminating comments the prisoner claims to have heard from the accused who has been in custody awaiting trial.
The failings of the practice have been laid bare this week with the disturbing revelations involving a prisoner who for years has been anonymised as Witness C.
The public now knows — but only after a long and costly battle to identify the prisoner and his criminal record — that Witness C, one of three secret informants called by the Crown in the 1990 murder prosecution of David Tamihere, is double murderer Roberto Conchie Harris.
It is a stain on the system that it took yet another inmate, the "jailhouse lawyer" Arthur Taylor, along with barrister Murray Gibson, to succeed with a rare private prosecution to expose Harris as a liar.
Harris was convicted last year on eight counts of perjury arising from the Tamihere trial.
He was sentenced by Justice Christian Whata to eight years and seven months jail, a term which reflects the seriousness of lying on the witness stand. The judge did not mince words when he called Harris' offending a "brazen assault on the foundation on our criminal justice system."
This goes to the heart of the use of prison witnesses. When inmates take the stand to testify against another prisoner, it is critical for the administration of justice that safeguards are in place to protect the defendant and the integrity of the system.
The unmasking of Harris as Witness C and his perjury conviction is the first time that a jailhouse informant has been successfully prosecuted. The Crown has never charged an informant for perjury, yet the evidence from other jurisdictions shows that miscarriages of justice have occurred as a result of perjured testimony.
In the United States and Canada, steps have been taken to strengthen the system to prevent it being manipulated.
These include pre-trial hearings, disclosure of an informant's criminal history, benefits received, cautions from the bench and a limit of one information per case. In New Zealand juries are warned that a prison witness may be unreliable but beyond that limited protection the system has been deemed adequate.
This week's disclosures indicate justice is not being served by the current approach.
On Thursday, approached about the use of "snitches" Justice Minister Andrew Little said: "We've seen so many cases now where jailhouse snitches have proven to be, frankly, abject liars and from a justice system point of view it's a waste of time and resources to have cases reliant on their evidence, and I think it's time to review that. It is a matter for police and Crown Law to see if they want to continue to have jailhouse snitches. We should have a closer look to see if this practice should continue."
Yesterday the minister seemed to back away from his position. "There's nothing on the plan at the moment, I'm not proposing to initiate anything myself."
He said there were disclosure rules already in place to reveal previous convictions of those giving evidence.
His apparent change of mind is unfortunate. Next week the Herald will publish the results of detailed inquiry into the use of prison witnesses. The conclusions are inescapable. The maintenance of a fair system of justice rests on transparency if miscarriages are to be prevented. Our current system, at least in this respect, falls short of this standard. It needs to change.