Mr Chapman grew up in Bootle, Liverpool, and transferred to RAF Halton during the Second World War. In 1945 he met and married Margaret Dickinson, who had been evacuated to Aylesbury from London. Their first home was a bedsit in Stonehaven Road, but they moved into Cromwell Avenue once a council house was available.
It was the death of their first child, Vivian, who died aged four weeks at Ashridge Houses' emergency Second World War medical facility, which sparked Mr Chapman's interest in the spiritual world. Encouraged by a colleague from Aylesbury Fire Brigade, where he then worked after being demobbed, he used a ouija board to make contact with his daughter.
Soon he was acting as a medium to a variety of entities, but Dr Lang, who had died in 1937, became the most prominent. In 1956 Dr Lang's family said publicly that the speech and mannerisms that Mr Chapman portrayed were a perfect match, and some of the things he talked of would only have been known to close friends. The doctor 'explained' to him that his mission was to heal the sick.
Mr Chapman left the Fire Brigade in the same year to devote more time to healing, and by the 1960s he had become world-renowned.