A judge has thrown out a Crown case against 21 accused because police fooled a court into prosecuting an undercover officer.

Justice Simon France has ordered a stay of proceedings in prosecutions of those arrested as part of Operation Explorer. It was a police crackdown on motorcycle gang members.

An undercover officer using the name Michael ‘Wiremu’ Wilson infiltrated the Red Devils in Nelson and police orchestrated a false arrest to boost his criminal credentials.

As a part of the operation Justice France said a fake warrant was prepared.

''This fake warrant, unappealingly described to me by the officers involved as 'a prop', purported to be signed by a judicial officer... The police scrawled an apparent signature... asserting the warrant had been issued by a deputy registrar, name indecipherable.

"However one looks at it, a fraud is being committed on the courts."

Justice France also said it appeared the police conduct had components of committing criminal offences.

''The search warrant would seem to engage section 256 of the Crimes Acts 1961 and the swearing of a false information would seem to engage section 110 of the Crimes Act.''

COURT ENGAGEMENT

Two police officers told the High Court at Nelson that they had earlier followed police protocols in approaching then Chief District Court Judge (the late) Russell Johnson to ask his permission.

However, the court later learned the manual had been written after police had pursued the false prosecution and recalled the officers to testify again.

The previous manual - existing at the time the officer approached the judge -  said: ''The police must not allow an arrested agent to appear under a fictitious name without the permission of the court. Deceiving the court is not permitted.''

Justice France said he accepted Detective Superintendent Drew had not meant to mislead the court. But it was ''unwise'' not to seek legal advice about the fake prosecution.

He also said a letter presented to the judge was ''wholly inadequate to alert the Chief Judge to the realities of what was involved''.

PRESSING NEED

In Justice France’s ruling, he said police believed the ''emerging prominence'' of the Red Devils was a forerunner to it becoming a chapter of the Hells Angels.

Officers obtained warrants to intercept telephones, text messages and to install listening devices.

They also infiltrated the club with two undercover officers posing as a couple.

However, there was always ''a level of suspicion'' among club leaders about ‘Wilson’, the judgment reveals.

His handlers were concerned he would be exposed and devised a strategy to ''strengthen his credibility''.

They obtained the fake search warrant for a storage lock-up rented in ‘Wilson's’ name.

Police wrongly believed the owner was involved with the club.

Police placed in the lock-up some ''apparently stolen'' equipment, as well as items associated with cannabis.

''On its face the warrant appears genuine,'' Justice France said.

Police then called in the lock-up owner and showed him the warrant - and then the contents.

‘Wilson's’ handlers then called a meeting and decided to go ahead with the ruse by pursuing a prosecution.

‘Wilson’ was charged with possessing equipment to cultivate cannabis in May 2010.

A police officer, known as Constable X, swore a ‘false oath’ to the court. ''

MW had not committed such an offence, and Constable X did not suspect he had,'' the judge said.

Police expected ‘Wilson’ to plead guilty ''reasonably quickly'', but on advice from gang members he decided to get a lawyer and the process became protracted.

Police decided to go along with this to boost ‘Wilson's’ standing - and that if he failed to appear before the court it would boost his credibility.

Two warrants had to be issued and a further charge of breaching bail was added.

The owner of the storage facility ''has certainly been the victim of improper police conduct", the judge said.

And the ''the court's processes can truly be said to have been abused, first by the use of the warrant, and second, by the laying of a false charge''.

He said judges had been treated ''in a disrespectful way". A prosecutor and the defence lawyer were also misled.

He also concluded it was ''a fundamental and serious abuse of the court's processes".

Justice France said: ''The courts are not part of police investigation. There is and can be no suggestion of collaboration. The court is independent, and sworn to treat all who come before it equally and without favour.''

Justice France also said he was ''surprised'' by the lack of insight by the officers ''about the lack of propriety involved".

POLITICAL FALLOUT

Green party co-leader Russel Norman said it appears the police were playing ''fast and loose with the courts''.

''The courts are there in order to protect the rule of law. If the police start playing fast and loose with the courts they are fundamentally undermining the rule of law. In this case it has worked out pretty bad for them.''

He said the involvement of Detective Inspector Grant Wormald in this case and the Dotcom case raises concerns.

''I know the police have got a pretty tough job, but they do need to follow the law and they do need to respect the court system... it's very important that they change their ways.''

Operation Explorer was headed by Wormald, who also supervised the joint FBI-police raid on Kim Dotcom's Coatesville home for the Organised and Financial Crime Agency.

He is facing allegations he lied under oath about illegal spying on the German millionaire.

In a court hearing last month Dotcom's lawyer, Paul Davison, accused Wormald of giving "inconsistent" testimony about surveillance by Government Communications Security Bureau (GCSB) on behalf of police.

Wormald had told the court no other agency had been involved in the spying - but it has since emerged GCSB was illegally monitoring communications from Dotcom and his co-accused, Bram van der Kolk, for a month before his January 20 arrest.

Dotcom's legal team have indicated they will lay a complaint with the Independent Police Conduct Authority.Police Minister

Anne Tolley said police had given her no indication if they will appeal the ruling. She said she has confidence in the police.

''Those guys are out there every day keeping our communities safe from the thugs.''

She wouldn't comment on the actions of Wormald. But she added: ''I'm just disappointed that gang members have not been brought to justice...I'm sure police are just as disappointed.''

However, she has not sought assurances from police on their undercover protocols because it is ''operational".

- © Fairfax NZ News