It is one of the most comprehensive demonstrations to date of how AI analysis of a selfie could help assess a patient’s health and potentially guide their medical care, and was trained on data from more than 40 million facial photographs across a range of ethnicities and ages.

Details of the breakthrough were published in the Lancet Digital Health journal.

The system can estimate a person’s biological age – the age a person looks, rather than their actual, chronological age – and predict the chances of survival for cancer patients from an ordinary photograph of their face, according to the results of a study that examined the model.