Andrew Bridgen has formally begun a libel action against Matt Hancock following a row over a tweet.

After Mr Bridgen tweeted that the Covid-19 vaccination programme was “the biggest crime against humanity since the Holocaust”, the former health secretary described his comments as “disgusting and dangerous antisemitic, anti-vax, anti-scientific conspiracy theories”.

At an event in Westminster on Wednesday, held to announce Mr Bridgen’s defection to the Reclaim Party, the North West Leicestershire MP said he has submitted a defamation claim against Mr Hancock to the High Court.

He said: “The basis of my claim is that Mr Hancock’s accusation of antisemitism against me is a false slur to deliberately try and shut down valid concerns raised by me on behalf of my constituents and thousands of others around the world about the safety and efficacy of the experimental Covid-19 injections.

“This issue is of international importance because every elected representative should be allowed to challenge Government policy without being shut down by malicious slurs.”

Mr Bridgen, who was expelled from the Conservative Party over his claims, launched a crowdfunding campaign to pay for the legal action, which has so far been supported by Reclaim The Media, an offshoot of the Reclaim Party.

The funding campaign webpage said the MP was looking to raise £250,000, with more than £14,000 already pledged.

A spokesman for Mr Hancock said: “Matt will defend this absurd action, which is a pathetic publicity stunt.

“The claim has no credible basis and, when Matt wins the case, he will also seek to recover all costs.

“Vaccines save lives, and Matt will always defend science and progress against unfounded conspiracy theories that put people’s health at risk.”