In a separate interview, also supplied by the clinic, she describes his improvements four weeks later, saying he makes sense 90 per cent of the time now, compared with none of the time before treatment started.

But five minutes after being injected with etanercept – according to the film which was supplied and edited by the clinic – he greets his wife. Visibly shocked, she says he has not recognised her for years. Mr Miller then hugs her.

Discovery of the decade? Injection 'could cure Alzheimer's in minutes'

Scientists claim videos are proof of breakthrough

An injection that dramatically relieved the symptoms of Alzheimer's disease within minutes would qualify as the discovery of the decade. That is exactly what was claimed yesterday for an experimental treatment being tested in America.