On 8 January 1966, the British Medical Journal published a paper by Doctors Ida MacAlpine and her son, Richard Hunter, entitled ‘The Insanity of King George III: A Classic Case of Porphyria’. This dramatic paper claimed that the king had suffered from attacks of intermittent acute porphyria, the Swedish type. In their case history the MacAlpines described five attacks between 1765 and George III's death in his 82nd year. A full account of the story is published in the second edition of my book The Porphyrias: A Story of Inheritance and Environment (1971). The MacAlpines were unable to find anyone among the many living descendants of George III who had acute intermittent porphyria but, in spite of this, they claimed in the paper: ‘The study allows the certain conclusion that George III's malady was not “mental” in the accepted sense, in whatever old or modern terms it may be couched. His long sorrowful illness, in which he suffered severely from his affliction, pitifully from his treatment and miserably from his management, takes on a new importance in the annals of medical history as the first description of a rare metabolic disorder not even today fully understood.’

When I was in England in December 1967, I called on the famous porphyrin biochemist Professor Claude Rimington who had collaborated with Ida MacAlpine and Richard Hunter on a second paper. The paper claimed that not only did George III suffer from porphyria, it was now porphyria variegata, but made the astonishing (and, if it were confirmed, epoch-breaking) claim that many members of the royal families of Europe from the time of Mary Queen of Scots had suffered from acute attacks of porphyria variegata.I asked Professor Rimington how many living descendants of Mary Queen of Scots had been found to have porphyria variegata, pointing out that at that time we had at least 10,000 porphyrics in South Africa who had inherited the disease from one ancestor who had come to the country 300 years before.