The Prime Minister has said social media firms must share the responsibility for the rising spread of measles in the UK as he attacked antivax misinformation.

Boris Johnson will on Monday set out plans to improve vaccination rates on a visit to a hospital in the South West, following a rise in cases of measles.

In the first quarter of 2019 there were 231 confirmed cases of measles, just three years after the World Health Organisation declared the UK measles-free.

Earlier this year Simon Stevens, the head of the NHS, said “fake news” by anti-vaxers on social media had fuelled a tripling in measles cases and added that the promotion of misguided messages on Instagram and YouTube was one of the factors behind the dip in vaccinations.

Ahead of the visit, Mr Johnson, who will call a summit of social media companies to discuss how they can play their part in promoting accurate information about vaccination, said: "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.