More than 200,000 people have called on ministers to break contracts with Palantir in an apparent groundswell of public concern about the US tech company’s role in the NHS, police, military and councils.

Two petitions have attracted 229,000 signatures, one calling for the government to end all public contracts with the company, the software of which is used by Donald Trump’s ICE immigration enforcement programme and the Israeli military, and another urging the health secretary, Wes Streeting, to cancel its £330m patient data contract with the NHS.

This week, the Guardian revealed the Metropolitan police was in talks to use the company’s AI to analyse sensitive intelligence, and Palantir published a manifesto described by one MP as the “ramblings of a supervillain”.

But the tech company is pushing back against the multipronged campaign challenging its work in the UK by taking issue with claims made widely on social media by the Green party leader, Zack Polanski, and the legal campaigner Jolyon Maugham, who this week launched a podcast investigation into Palantir. The Liberal Democrats are also calling for the NHS contract to be cancelled and new contracts to be halted.

Matthew McGregor, the chief executive at 38 Degrees, the campaigning organisation that promoted the petitions, said: “Almost a quarter of a million people have said loud and clear: they don’t want a company like Palantir, whose technology is used by ICE and the Israeli army, to have access to their most sensitive data.”

Referring to the manifesto that was published by the company’s US operation at the weekend, which said free and democratic societies need “hard power” to prevail, he added: “The government need to act fast and trigger the break clause on these lucrative contracts now.”

Palantir has £600m worth of contracts with UK public bodies and may soon extend that, with talks continuing with Scotland Yard to use the company’s AI technology to automate intelligence analysis for criminal investigations. If a deal is confirmed it would represent a significant expansion in Palantir’s involvement in UK law enforcement. It also has a £240m contract with the Ministry of Defence and has this week renewed a contract with Coventry city council thought to be worth £750,000. It also has deals with Bedfordshire police and Leicestershire police, among other constabularies.

Palantir’s UK chief executive, Louis Mosley, has been seeking to rebut criticism of the company, sometimes using internet memes, in what has become a highly public PR fight.

Maugham used social media to describe the Good Law Project’s podcast as looking into “what happens when you take an antichrist-obsessed billionaire and a company named after an evil seeing stone in The Lord of the Rings and you put them at the heart of the NHS”.

Moseley responded by posting a meme from the US sitcom It’s Always Sunny in Philadelphia, suggesting critics were engaged in a conspiracy theory.

He also posted on X: “Note to diary: box @ZachPolanski [Polanski’s actual X account is @ZackPolanski] Tuesday, wrestle Jolyon Maugham on Thursday. Leaving Friday open in case @EdwardJDavey fancies a fencing match.”

Polanski’s campaign against Palantir has been equally vigorous, but not always accurate. This week he launched an online video which claimed wrongly that Peter Thiel was its chief executive and called it a spyware company. Moseley challenged this and called it “technically defamatory” as spyware is illegal malicious software that enters a user’s computer, but he added “don’t worry, we are not suing”. Thiel, a Trump-supporting tech billionaire, was Palantir’s co-founder.

“We have a chance to get this dangerous company out of our NHS and all of our public services,” Polanski said. “Ministers must listen to the public and end this appalling contract now.”

Palantir says its software helps increase the number of NHS operations carried out, reduces the time it takes to diagnose cancer, keeps Royal Navy ships at sea for longer, and protects women and children from domestic violence.