Anti-vaccine campaigners who spread “mumbo jumbo” and “nonsense” on social media are “completely wrong”, Boris Johnson has said.

Speaking to broadcasters during a visit to a vaccination centre in Moulton Park, Northampton, the Prime Minister said a “voluntary approach” to vaccination will remain, amid other countries’ “coercion”.

He said: “I want to say to the anti-vax campaigners, the people who are putting this mumbo jumbo on social media: they are completely wrong.

“You haven’t heard me say that before, because I think it’s important we have a voluntary approach in this country and we’re going to keep a voluntary approach.”

Mr Johnson said other European countries are going for “coercion”, and added: “What a tragedy that we’ve got all this pressure on the NHS, all the difficulties that our doctors and nurses are experiencing, and we’ve got people out there spouting complete nonsense about vaccination.

“They are totally wrong, and I think it’s time that I, the Government, call them out on what they’re doing.

“It’s absolutely wrong, it’s totally counter-productive, and the stuff they’re putting out on social media is complete mumbo jumbo.”

The vaccine rollout has successfully reached tens of millions of people, with a ramping up of the booster programme in recent weeks as Omicron cases surge.

However, an estimated 4.5 million people aged 18 and over in the UK have not had a first dose, more than six million people are not double jabbed, and almost nine million eligible people have not had a booster.

There are multiple reasons for people not getting vaccinated, including them questioning whether it is necessary, safe or effective, concerns about side-effects, complacency due to lower perceptions of personal risk, historic distrust of some public services, and misinformation.

Some people will have valid medical exemptions, and millions who have recently contracted coronavirus will be unable to get a booster until 28 days after their positive test.

Mr Johnson’s comments follow remarks by chief medical officer Sir Chris Whitty earlier this week, who said he was frustrated that some people being deliberately scared away from the lifesaving jabs by misinformation.