Stephen Young, 35, an insurance broker, of Pembury Kent, was given a life sentence last March after being convicted of murdering newly-wed Harry and Nicola Fuller at their cottage in Wadhurst, East Sussex. He will remain in custody pending a retrial at the Old Bailey before a new jury.
Yesterday's ruling came after the Court of Appeal had read statements from all 12 jurors at the original trial and two jury bailiffs.
However, Lord Taylor, the Lord Chief Justice, made an order under the Contempt of Court Act banning publication of the contents of the statements until after the retrial.
David Penry-Davey QC, Mr Young's counsel, had told the court that jury members had used a Ouija board while staying overnight at a hotel, before returning verdicts. He argued that was a material irregularity going to the root of the trial.
Their actions constituted an 'experiment' or consideration by the jurors of matters additional to the evidence in the case. If it had come to light before the verdicts were given, the trial judge would have had no option but to discharge the jury.
But Michael Lawson QC, for the Crown, contended that what happened was an internal matter between the jurors and the court should not intervene.
He said there was nothing to suggest that the jurors broke their oath to try the case according to the evidence, or that their unanimous verdict was tainted by what happened.
The court should not 'elevate a drunken experiment' into a recognition that it had some practical effect, Mr Lawson said.
The appeal judges are to give their full reasons for quashing Mr Young's conviction and ordering a retrial at a later date.