Google has stoked fears in the UK regarding its access to private medical data after the decision was made to transfer part of its London health operation to US hands.

The company’s London-based AI lab DeepMind announced yesterday that its DeepMind Health unit would be absorbed by Google Health. DeepMind Health is responsible for a range of health care projects in the UK, including the Streams app, which is used by a small number of doctors and nurses working in the UK’s National Health Service (NHS).

The creation of the app was controversial. Last year, the UK government ruled that DeepMind had gained inappropriate access to medical data from 1.6 million patients when developing Streams. By the time of the ruling, DeepMind had already redrawn its contracts with the NHS, and the unit’s chief, Mustafa Suleyman, reassured the public of its intentions.

In a blog post, Suleyman wrote, “DeepMind operates autonomously from Google, and we’ve been clear from the outset that at no stage will patient data ever be linked or associated with Google accounts, products or services.”

Critics say DeepMind has broken this promise, while DeepMind says the data is not at risk. “All patient data remains under our partners’ strict control, and all decisions about its use lie with them,” said a spokesperson for the AI lab. “This data remains subject to strict audit and access controls and its processing remains subject to both our contracts and data protection legislation. The move to Google does not affect this.”

“That is an atrocious breach of trust.”

Medical privacy experts say this is beside the point. Julia Powles, a researcher who co-wrote a paper on DeepMind’s deals with the NHS with journalist Hal Hodson, said, “Making this about semantics is a sleight of hand. DeepMind said it would never connect Streams with Google. The whole Streams app is now a Google product. That is an atrocious breach of trust, for an already beleaguered product.”

Sam Smith, a researcher for UK advocacy group MedConfidential, said the move felt unavoidable. “The people in Silicon Valley really don’t care what the hippies in London want,” Smith told The Verge. “DeepMind and Mustafa [Suleyman] were adamant they wouldn’t give data to Google, but that that didn’t cover Alphabet giving all of DeepMind Health to Google.”

The move doesn’t include all of DeepMind Health’s projects, though. The parts of the health unit dedicated to pure research — like those developing algorithms that can predict eye disease and breast cancer — will remain under DeepMind’s control. Only the team working on commercial applications (like the Streams app) will move to Google.

As part of the move, DeepMind will likely be jettisoning its independent review panel, which was created to oversee its deals with the NHS. A spokesperson for DeepMind said this was because the panel “was a governance structure for DeepMind Health as a UK entity. Now [it] is going to be part of a global effort so this is unlikely to be the right structure in the future.”

Many questions remain, particularly about whether deals signed between NHS hospitals and DeepMind Health will have to be renegotiated. Smith says hospitals like Royal Free — the only hospital that currently uses the Streams app with patients — could back out from the deals due to break clauses in their contracts. But this would cause embarrassment for both the NHS and DeepMind, and it could possibly stymie future projects.

In a statement given to The Verge, Dominic King, leader of DeepMind’s Streams team said: “At this stage our contracts have not moved to Google and nothing has changed in terms of where the data we process is stored. Nothing changes until Trusts consent and undertake any necessary engagement, including with patients.”

The Streams app itself is also going to change. DeepMind previously stressed that it was not using AI within the app. But as part of the announcement yesterday, it said Streams would now be developed into an “AI assistant” for nurses and doctors, helping alert them to patients in trouble. It’s not clear if this AI analysis will be applied to the 1.6 million patient records that the Streams app has access to.

Whatever happens next, DeepMind’s presence in the UK has changed irrevocably. The lab has always boasted about its independence from Google — a line that was part defensive, part proud. Now, it seems hollow. If Google can take control of DeepMind’s most sensitive project in the UK, what else might it want to grab? This knowledge will presumably make would-be partners think twice before handing over their data and research to DeepMind and, by extension, Google.