Speaker: Professor Timothy Peters (University of Birmingham)

Considerable doubt has been cast on the claim that King George III suffered from acute porphyria. The alternate diagnosis of recurrent acute mania is much more in keeping with his clinical features, but historians and their adherents still claim that suggestive features of acute porphyria in some of his ancestors, notably King James VI/I, support a diagnosis of porphyria in George III.

Assessment of his detailed and complex clinical history and features using the computerised diagnostic aid SimulConsult provides no support for porphyria in James but indicates a quite unexpected diagnosis that may help to explain the King’s medical condition and psychological behaviour.