Prime minister seeks to halt rise of measles after more than 230 cases in three months

Boris Johnson will call on social media companies to do more to stop anti-vaccination messages spreading online as he visits a hospital in the south-west of England.

The prime minister will lay out his plans to halt the resurgence of measles in the UK after more than 230 cases were diagnosed in the first quarter of the year.

He will not go so far as to give his backing to mandatory vaccination, which is not being ruled out by Matt Hancock, the health secretary. But he will set out plans for the UK to regain its lost “measles-free” status.

NHS England will be asked to write to all GPs urging them to promote catch-up vaccinations for older children and those who missed out on a second booster jab.

Johnson’s central idea is to call a summit of social media companies to discuss how to ensure that only accurate information on vaccinations is disseminated, at a time when anti-vaccination material has spread wildly online.

Unicef released figures this year showing that more than half a million children in the UK went unvaccinated against measles between 2010 and 2017. Anti-vaccine messages on social media have been blamed for promoting scepticism among parents.

Johnson will call for the NHS to meet a target of 95% of children receiving both doses of the MMR vaccine, which protects against measles, mumps and rubella. Just 87% now get both jabs.

“After a period of progress where we were once able to declare Britain measles-free, we’ve now seen hundreds of cases of measles in the UK this year. One case of this horrible disease is too many, and I am determined to step up our efforts to tackle its spread,” Johnson will say.

“From reassuring parents about the safety of vaccines to making sure people are attending follow-up appointments, we can and must do more to halt the spread of infectious, treatable diseases in modern-day Britain.”

Hancock, who ran for the Tory leadership before supporting Johnson, said he wanted the whole health system to come together to renew focus on vaccinations with the aim of eliminating measles for good. He has previously said campaigners against jabs for diseases such as measles have “blood on their hands”.

Johnson is due to visit Cornwall on Monday where he will meet doctors and nurses. It is his second hospital visit in recent weeks amid speculation that he is preparing to fight an election promising to spend more on the NHS. The Vote Leave campaign in 2016 pledged an extra £350m a week for the NHS after Brexit.