The Court of Appeal has unanimously overturned a stay of criminal charges laid against 20 associates of the Red Devils motorcycle club, ordered after revelations of police misconduct during an investigation.
The High Court had stayed the charges due to the police misconduct during the probe into the activities of the Red Devils but the Court of Appeal's decision, released today, means the trials of the 20 respondents will now continue.
In 2009, police were investigating the emerging Red Devils Motorcycle Club, who they suspected were about to become a chapter of the Hells Angels.
During a crackdown, dubbed Operation Explorer, police bosses became concerned that an undercover officer known in the gang as Michael Wiremu Wilson was about to be exposed.
To strengthen his credibility in the gang, police arranged for a fake search warrant of his lock-up in which they had placed apparently stolen equipment and drug paraphernalia.
Police forged an illegible signature of a court deputy registrar, and arrested Wilson.
Wilson appeared on several occasions before judges, who all believed they were dealing with a genuine case.
Soon after Operation Explorer ended, police sought to have Wilson's charges withdrawn.
As a result of evidence gathered during the operation 21 associates of the Red Devils were charged with a range of offences, totalling 151 charges.
Only 20 of the defendants appealed to the Court of Appeal as one pleaded guilty in the High Court.
All the respondents applied in the High Court to have the charges against them stayed on the basis that the actions by police during Operation Explorer amounted to police misconduct so serious that to allow the trial to proceed would be an abuse of the court's process.
In the High Court, Justice Simon France said he believed police thought they were acting legitimately, but a letter police gave to a District Court judge about the situation would have been "wholly inadequate" to alert him to the realities of what was involved.
There was fundamental and serious abuse of the court's processes by the police, he said.
The Crown applied to the High Court for leave to appeal Justice France's decision to the Court of Appeal.
The High Court granted leave to appeal and concluded that the High Court judge was wrong to stay the prosecutions, although it was accepted by the Crown in the Court of the Appeal that the police actions amounted to serious misconduct.
Operation Explorer was overseen by Detective Inspector Grant Wormald, who also headed the joint raid on internet millionaire Kim Dotcom's mansion for the Organised Financial Crime Agency.