Tens of thousands of people have formally demanded NHS England blocks the Palantir-powered national medical data platform from handling their personal information.

More than 44,000 people have filed legal objections to their health data being shared with, stored in or used by the nationwide Federated Data Platform (FDP) operated using the US company’s AI technology.

The coordinated campaign utilises rights enshrined in data protection laws and means the NHS must stop using the data unless it can provide a “compelling reason” to continue.

Hundreds of thousands of people have signed petitions demanding the government cancels its £330m deal with Palantir, and Andy Burnham will be required to make a decision to back or axe Palantir within months.

Campaigners have voiced anger at Palantir’s work for the Israeli military and Donald Trump’s immigration crackdown, and two House of Commons select committees have called for Labour to exercise a break clause in the seven-year deal which comes into force in February 2027.

David Murray, a retired IBM systems engineer and one of those requesting the data block, said: “I am a believer in the NHS having really good data on their patients, but I want it to be something you can really trust to be used for the right purposes. I am not happy about Palantir’s involvement with the IDF in Gaza and ICE in America.”

On Wednesday, the human rights group Amnesty International and patient campaign group, Just Treatment, parked a van styled like a shot-up Palestinian ambulance outside Palantir’s London HQ in a stunt that asked: “Why should a company linked to Israel’s destruction of Gaza’s healthcare system have any place in ours?”

Protesters have also raised concerns, acknowledged by the NHS England chief executive, Jim Mackey, that the benefits to public health from the Palantir-powered platform may not be as significant as has been claimed.

Palantir says the FDP, which is designed to connect sprawling health service data on topics ranging from surgery schedules to discharge planning, is helping to cut waiting lists and frees up beds. Louis Mosley, the company’s executive vice-president for UK and Europe, has accused people who disagree with that assessment of suffering from “Palantir derangement syndrome”.

A spokesperson said: “Palantir software is helping to deliver better care, with trusts using it recording 117,000 additional operations, a 14.3% reduction in discharge delays for long-stay patients and a 5.6% improvement in the number of people finding out whether or not they have cancer within 28 days.”

Mosley has said its technology was used for locating hostages, not military targeting, in Gaza, although when challenged last year by a protester alleging “Palantir kills Palestinians” in Gaza, the company’s chief executive, Alex Karp, replied: “Mostly terrorists, that’s true.”

The formal objections to the FDP using personal data cite article 21 of the UK General Data Protection Regulation and express concern that “the involvement of Palantir undermines my personal trust in NHS data confidentiality”. Palantir said its patient data could only be handled according to the NHS’s instructions and remained in the UK.

Veronica Hawking, the campaigns director at 38 Degrees, a not-for-profit that coordinated the data objections, said: “The scale of this public backlash should be a huge wake-up call for the government.”

A spokesperson for NHS England said: “All NHS organisations remain in control of their data within the FDP, with suppliers unable to access it for their own purposes, and we will respond to the objection requests in line with data protection law.”

The 44,000 objectors have also asked that the NHS halts processing of their data through the Palantir platform while their main request is assessed.