The conman knocked on the door of the pensioner in Surbiton, southwest London, on December 30, claiming to work for the state-run National Health Service (NHS).

She let him into her home, where he jabbed her in the arm with a “dart-like implement” before asking her for £160 ($217, 177 euros), which he said would be refunded.

The City of London Police, which investigates frauds and other scams, said it was not known what substance was injected, but the victim showed no ill effects.

“It is crucial we catch him as soon as possible as not only is he defrauding individuals of money, he may endanger people’s lives,” said Detective Inspector Kevin Ives.

Meanwhile, Northern Ireland police warned internet users about a phishing scam in which they are told they are “eligible” for a vaccine before being asked for bank details.

Britain began a mass vaccination programme on December 8 last year, prioritising care home residents and workers, the over-70s, and other vulnerable groups.

AFP