Boris Johnson has said people opposed to vaccinations are “nuts” as he promoted an expanded programme of NHS flu jabs.

During a visit to a medical centre in east London, the Prime Minister asked staff what they thought of anti-vaxxers, adding: “There’s all these anti-vaxxers now. They are nuts, they are nuts.”

It comes after several polls have suggested some Britons are feeling apprehensive about having a Covid-19 vaccine.

A coronavirus jab is seen by many experts as a key route out of the pandemic.

The anti-vaccination movement has been growing globally in recent years, fuelled in part by social media.

A paper published in The Lancet in 1998 by Dr Andrew Wakefield – and since widely discredited – suggested a link between the measles, mumps and rubella (MMR) vaccine and autism in children, which led to a huge drop in MMR vaccine rates.

Last year, the World Health Organisation identified “vaccine hesitancy” as one of the top 10 health threats to the world.