Mark Lundy is set to be retried for the murders of his wife and daughter in the High Court of New Zealand after the Privy Council quashed the convictions tonight.
Lundy, who is serving a minimum prison sentence of 20 years, was found guilty of murdering wife Christine and daughter Amber, 7, in a frenzied attack in their Palmerston North home in August 2000.
He maintained his innocence and the Privy Council, in London, heard a three-day appeal against the convictions in June.
Just after 9pm, the Privy Council announced its decision, saying its board had to consider whether Lundy's convictions were "safe" given the nature of evidence emerging after trial.
The test as to whether the conviction was "safe" was whether the new evidence would have led to an acquittal. The Privy Council board said in light of the new evidence Lundy's conviction could not be considered safe.
"Since the trial a substantial body of evidence from reputable consultants has cast doubt on the methods the Crown had relied on to establish the time of death based of the post mortem examination of the victims," The Privy Council said.
"Furthermore the use of the particular method used to identify the tissue as central nervous system tissue is controversial, both in criminal trials generally, because it is relatively untested in that context and in the particular circumstances of this case, where there is at least reason to doubt the accuracy of the testing given the state of the samples.
"Finally, evidence produced by the appellant suggested the tampering to the computer had an innocent explanation in that it had been caused by a virus that had not been detected by the Crown's witness."
The Privy Council said it was right for the case to be retired, rather than sent to the Court of Appeal, "because the divisions between the experts are so profound".
"They range over so many areas and they relate to matters which are so central to the guilt or innocence of the appellant that they may only be properly be resolved by the trials of fact in a trail.
"The board will therefore humbly advise her majesty that the appeal should be allowed, that the convictions should be quashed and the appellant should stand trial again on the charges of murder as soon as that can be conveniently arranged."
It said Lundy should remain in jail until the retrial, but the New Zealand High Court would be free to rule on any application from Lundy to be freed until the trial.
Police respond to Lundy decision
Assistant Police Commissioner Grant Nicholls responded to the legal decision with a statement, saying it would "discuss the Privy Council's judgement with Crown Law and the Crown Solicitor to determine the next steps.
"This is likely to include evaluation of what evidence needs to be prepared and the availability of witnesses."
He said it was inappropriate to discuss details of the case at this time.
The Privy Council's options
The Privy Council had the choice of upholding the convictions or quashing them.
After quashing the convictions, it had the choice of ordering a a re-trial or, as discussed during the June hearing, sending the case to the Court of Appeal.
Lundy's appeal was led by London-based former New Zealand lawyer David Hislop. No Crown Law Office prosecutors were present in London for the Privy Council verdict.
Lundy was found guilty of the murders at a 2002 jury trial in Palmerston North.