The woman who was suspected of spying after she revealed secret wartime information during a seance was jailed for nine months under a 200- year-old law.
As her story is about to be turned into a film, supporters of the Dundee housewife with six children, hailed as spiritualism's greatest heroine and martyr, are stepping up their campaign to clear her name.
After years of compiling evidence to show her conviction by an Old Bailey jury in 1944 was unsafe, campaigners have launched a plea for legal help to take their case to the Criminal Cases Review Commission. The campaign has attracted global support with more than 20 million people from as far afield as China, Taiwan, Russia, North Korea, Iraq, Iran and Iceland logging on to its website.
Throughout the 1930s and 1940s, Duncan travelled the country giving seances. During the war, women sought reassurance about their men. During a sitting in Portsmouth in 1944, Duncan was apparently in contact with a dead sailor, who greeted his mother. His mother had not, however, known he was dead because the Admiralty had concealed the news of the sinking of his warship, HMS Barham, for security reasons.
Duncan was arrested and accused of vagrancy, later changed to conspiracy, a hanging offence in wartime. But in court the charge was "contravening the Witchcraft Act of 1735", because she admitted "attempting to bring about the appearances of the spirits of deceased persons".
Duncan took an admission fee, so she was also charged with taking money under false pretences. She was found guilty under the Witchcraft Act but innocent of all other charges. The right to appeal to the House of Lords was withheld.
"We want to clear her name," said Michael Colmer, campaign co-ordinator and editor of Psychic World magazine. "There are signs that the trial of Helen Duncan was a cover-up."
Her supporters say the jury was misinformed when it was told Duncan had been convicted of fraud in Edinburgh in 1933.
Work has begun on a film of her story, which has a working title of The Witchcraft Conspiracy.
Duncan later resumed her work as a medium, but was never as successful and died in 1956 at home in Dundee. Her grandson, Jack, who lives in the US, has pledged support.
Mr Colmer said: "We now need the pro bono services of a barrister familiar with applications to the CCRC."
The Witchcraft Act was repealed in 1951.Reuse content