'Anti-vaxxers are nuts': Boris Johnson

British prime minister Boris Johnson on Friday described people opposed to vaccinations as "nuts", as he promoted the government's expanded programme of flu jabs.

"There's all these anti-vaxxers now. They are nuts, they are nuts," he said as he toured a medical centre in east London.

Johnson's government has widened its winter flu vaccination programme, given fears that combined with a second wave of coronavirus infections, health services could be overwhelmed.

The vaccine will be free for the most vulnerable groups, including older people, those with underlying conditions, and younger children.

The Department of Health aims to vaccinate more than 30 million when the programmes gets under way later this year, it said in a statement.

Health secretary Matt Hancock called it "the biggest flu vaccination programme in history, and will help protect our NHS (National Health Service) as we head into winter".

Chief medical officer Chris Whitty said vaccination was a way of helping reduce "all avoidable risks", with coronavirus still circulating, and no vaccine yet available.

Experts commissioned by the government's chief scientific officer have warned that if no action was taken now, nearly 120,000 people could die in hospitals alone in a second wave.

The government is preparing for the possibility, and on Friday the wearing of facemasks became compulsory in shops across England.

In 2019, the World Health Organization identified "vaccine hesitancy" as one of the top 10 global health threats in tackling preventable diseases.

Earlier this month, a survey indicated that 16 percent of British adults would "probably" or "definitely" avoid a COVID-19 vaccine.

The study, by pollsters YouGov for the Center for Countering Digital Hate, found that respondents who get most of their news from social media were more likely to refuse a jab.

The anti-vaccination movement has gained ground on social media in recent years, including during the coronavirus outbreak.

One theory circulating online is that flu vaccines contain coronaviruses. Another says getting a flu jab can lead to a positive test for the virus.

But experts have dismissed both claims.