The Government has been accused of complacency as Labour analysis found dedicated anti-vaccination groups on social media with hundreds of thousands of members were continuing to pump out disinformation about coronavirus.

Labour said the closure of the Counter Disinformation Forum – which brought together social media companies, academics, fact-checkers and researchers to look into Covid disinformation – after a six-month trial meant more lives were being lost and pressure put on the NHS.

It comes as the Prime Minister said 90% of those in intensive care with Covid had not had their booster jab.

Labour has called for emergency legislation to criminalise companies that do not act to stamp out anti-vaccination content.

The party said the Government had not acted strongly enough, and had also not made the promised progress with the forthcoming Online Safety Bill.

It comes as Thames Valley Police appealed for information over an anti-vaccination protest at a vaccination centre in Milton Keynes on Wednesday.

Tory MP for Milton Keynes North Ben Everitt said of the protest on Twitter: “What a bunch of dickheads. The staff and volunteers at our vax centres do an amazing job. Nobody deserves this at work.”

He added that he hoped the police got the evidence they needed to “bring these morons to justice”.

Boris Johnson also visited a site delivering jabs in the town on Wednesday, where he said: “I’ve talked to doctors who say the numbers are running up to 90% of people in intensive care who are not boosted.”

Labour’s shadow culture secretary, Lucy Powell, said: “The continuing spread of vaccine misinformation online is hitting vaccine uptake, and tackling this is critical to getting the unvaccinated vaccinated.

“One person put off the vaccine by dangerous anti-vaxxers is one too many.

“The tech giants are failing to wipe out vaccine lies. The truth is that government complacency on fake news means they are failing to take action against online platforms that are facilitating the spread of disinformation. This is now a matter of life and death.

“The Government must stand up to big tech companies, ignore their excuses, and introduce financial and criminal penalties for failures that lead to serious harm.”

Labour said that long-term monitoring by the Centre for Countering Digital Hate of those spreading anti-vaccine and Covid denial content from the UK revealed nearly 1.5 million followers, including more than half-a-million followers on Facebook.

The party said the analysis also showed Facebook was still hosting accounts belonging to the Disinformation Dozen, the 12 anti-vaxxers responsible for up to 65% of anti-vaccine content on Facebook and Twitter.

Labour highlighted another account under the name of Dr Vernon Coleman branding Covid jabs as “murder” and said the shutting down of the Counter Disinformation Forum was a mistake.

Earlier this month, tech and digital economy minister Chris Philp said the forum “was a six-month pilot programme”.

But he added that “the DCMS (Department for Digital, Culture, Media & Sport) led Counter Disinformation Unit monitors for false and misleading narratives shared on social media”.

He said: “Where dangerous and incorrect claims about the virus are identified, these are flagged to the relevant platforms.”

The Government said the wider counter-disinformation unit still existed and “continues to work closely with social media companies to identify and remove dangerous disinformation about vaccines”.

A spokesperson said: “We have one of the highest Covid-19 vaccine uptake rates in the world and over the past year have been providing people with advice and information about vaccines in one of the most extensive public health campaigns ever launched.”

The spokesperson added that “tough new online safety laws” would force companies to take action.

“Now that Parliament has provided the necessary scrutiny of the legislation, we will introduce it as soon as possible,” they added.