Vaccinations could be made compulsory for schoolchildren under new plans being considered by the health secretary.

Matt Hancock said there was a “very strong argument” for mandatory immunisation following a rise in measles cases, which could see thousands of children prevented from going to school if they have not had their jabs.

As Tory activists descended on Manchester for the party’s annual conference, Mr Hancock told a fringe event that he had recently commissioned legal advice on the matter.

His comments mark a major shift, as Mr Hancock said he would “rule nothing out but I don’t want to reach that point” when asked about compulsory vaccinations earlier this year.

Asked about the move at a HuffPost fringe event, he said: “When the state provides services to people, it is a two-way street. You’ve got to take responsibility too.

“I think there is a very strong argument for having compulsory vaccinations for children for when they go to school because otherwise they are putting other children at risk.

“You’ve got to make sure the system would work because some children can’t be vaccinated, some may hold very strong religious convictions you would want to take into account.

“But frankly the proportion of people in either of those two categories is tiny compared to the 7 or 8 per cent now who don’t get vaccinated.”

He said it was “unbelievable” that the UK had lost its measles-free status from the World Health Organisation.

Mr Hancock, a former Tory leadership hopeful, added: “I think there is a very strong argument for moving to compulsory vaccination and I think the public would back us.”

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Asked if he would take legal advice, he said: “I have actually received advice inside government this week on how we might go about it and I’m looking very seriously at it.”

His change of attitude to compulsory vaccinations comes after Boris Johnson launched a new campaign to combat the spread of anti-vaxx information, amid fears social media misinformation had led to a decline in take-up.