Of all the suffering endured during the Second World War, the brief imprisonment of Helen Duncan, a Scottish grandmother who claimed to have paranormal powers, was a minor injustice at worst. But, six decades later, it is still causing hubble, bubble, toil and trouble.
Mrs Duncan was one of the last people in Britain to be convicted under the 1735 Witchcraft Act. Yesterday, the Scottish Parliament received a petition with more than 200 signatures, demanding that she be given a full posthumous pardon. It was organised by Full Moon Investigations, a team of Scottish ghost-busters who claim to have paranormal gifts.
During the war, Mrs Duncan made several visits to Portsmouth where the desperate relatives of men killed or missing in action would flock to her seances, paying an admission price of 25 shillings a head – a huge sum in those days – hoping to hear the voices of their loved ones.
At one seance, she claimed to have made contact with a sailor from HMS Barham, a ship which had not been officially declared sunk. When it was announced, several weeks later, that the ship had indeed gone down, some took it as proof that Mrs Duncan was psychic. Others believed she had been tipped off and was giving away naval secrets to improve trade.
When she held another seance in Portsmouth, in January 1944, a plain-clothes policeman was waiting in the audience to arrest her the minute the first spirit from beyond turned up. She was sentenced to nine months in prison. After her release, she was more cautious about summoning the dead. She went off to join them in 1956, aged 59.
She was not, as is sometimes asserted, the last person convicted under the Witchcraft Act because six months later the same Act was use to jail a 72-year-old called Jane Yorke.
Her defenders at Full Moon Investigations are in no doubt that Mrs Duncan was a gifted medium persecuted by the authorities for fear of what else she might cause the dead to reveal. They see it as a late example of centuries of persecution of real or imagined witches, many of whom may have been faith healers, herbalists, or people who were either benevolent or just a bit cranky.
James VI of Scotland, who reigned in England as James I, was notoriously obsessed with witches, which was why writing Macbeth was a smart career move by William Shakespeare. Poor Agnes Simpson, the "grace wife of Keith", was interrogated by the king in person, then deprived of sleep and subjected to days of barbaric torture until she confessed to being the leader of 200 witches who rode out to sea in sieves at Halloween and enjoyed a rendezvous with Satan in North Berwick.
Members of the Full Moon team feel very strongly about injustices such as this, because they are themselves the sort of people who might have been burnt at the stake if they had had the misfortune to live in Tudor or Stuart times. Their website describes them as having "a wealth of knowledge in all aspects of the paranormal". Ewan Irvine, whose name heads the list of signatories of yesterday's petition, discovered his vocation as medium at the age of 19 after "many strange experiences that could not be explained logically".
There are still places in the world where being accused of witchcraft is life-threatening. Human Rights Watch has appealed this week to King Abdullah of Saudi Arabia to rescind a death sentence passed on anilliterate woman, Fawza Falih, who is accused of bewitching a man and making him impotent.
The main newspaper in Papua New Guinea, The National, reported the case this week of a woman seven months pregnant who was accused of sorcery when her neighbour suddenly died. Villagers hanged her from a tree. She gave birth while she was struggling to free herself. Mother and baby are in hospital.
The British authorities stopped taking witchcraft seriously nearly 300 years ago. The whole point of the 1735 Witchcraft Act was not to end witchcraft, but to end silly stories and phoney seances. The Act is like a forerunner to the Trade Descriptions Act; it made it illegal to con people into thinking you were performing magic.
Mrs Duncan already had a pre-war conviction for fraud, when during one her seances a guest grabbed at the shape of a ghost emerging from the other side under her skirt, and found it was a knitted elastic undervest.
At her trial at the Old Bailey, in 1944, Mrs Duncan's defence team called witnesses, including a founder of Psychic News, to convince the jury she really could summon the dead. They were more convinced by the evidence of Portsmouth's chief of police, who called her an "unmitigated humbug and pest".
William Colvin, an investigative journalist who launched the campaign to rehabilitate Mrs Duncan, is in no doubt that she was the innocent victim of a judicial frame-up, who had a "precious gift that brought comfort to thousands". Mr Colvin also concluded that Winston Churchill was a druid, who visited Mrs Duncan in prison. This is unlikely. A more plausible explanation is that she was a fraud who was rightly banged up for making money from the grief and gullibility of the bereaved. If I am wrong, no doubt I shall be turned into a toad.