Social media is being flooded by digitally created "deepfake" videos using the trusted identities of famous doctors to promote dangerous miracle cures for serious health problems, experts warn.

Videos on Facebook and Instagram have taken advantage of the credibility of star TV doctors to advertise untested "natural" syrups for diabetes, even claiming that the proven, first-line drug metformin "could kill" patients.

These scams risk endangering lives, experts said, particularly because they deploy the likenesses of popular health experts such as British TV presenter Michael Mosley, who died earlier this year.