His appeal will strike at the heart of the Home Secretary's wide-ranging powers to decide how many years murderers must remain in jail.
At present, the minister consults the trial judge and the Lord Chief Justice about the tariff sentence, which determines how long a life prisoner should serve before becoming eligible for parole.
At his appeal, Norman Parker's lawyers will tell the court that although Home Secretaries have wide discretion, they should be bound by juries' verdicts. Parker will claim that, in his case, the Home Secretary ignored the views of the jury, which became obvious at his trial in 1970.
He was found guilty of shooting dead a man who had previously been attacked by his business partner. Crucially, this partner was cleared of murder, a clear indication that the jury did not believe the killing to be pre-planned, Parker's lawyers will say. Further proof that the jury thought the murder to have been committed on the spur-of-the-moment came in a conversation between the jury foreman and the trial judge.
Yet in the mid-1980s, Parker discovered that his tariff sentence had been set at 20 years - a length reserved for the most serious category of murderers, including terrorists, sadists and child killers. His lawyers will say that, in other words, the Home Secretary thought that Parker was guilty of pre-meditated murder.
Parker, now 47, has subsequently been refused parole, a decision which he says must have been influenced by the length of the tariff sentence.
At a judicial review hearing in July, the High Court dismissed Parker's challenge to the Home Secretary, who it said was not bound by the jury's views and could take into account evidence not heard at the trial.
The court also said that as the Home Secretary's consultations with the trial judge and Lord Chief Justice were secret, it was impossible to say whether he had been misinformed or had ignored what he had been told.
However, Parker is preparing an appeal against the ruling. He will say the judgment is flawed because a Home Secretary's authority arises from a jury verdict, which cannot then be flouted.Reuse content