Babylon Health, which promotes its symptom checker chatbot as part of its digital GP business, said the tool had been used millions of times.
The chatbot asks users questions about their condition and is supposed to accurately triage what may be wrong with them. The company claims on its website that the tool uses the latest artificial intelligence technology.
NHS consultant oncologist David Watkins has raised concerns about the safety of the chatbot after recording examples of him using the chatbot where it appears to fail to recognise serious conditions including heart attacks from obvious symptoms he enters.
Babylon Health has previously attacked Dr Watkins for his criticisms of the technology and labelled him a “troll” but has acknowledged problems in 20 of his examples as “genuine errors” in the software.
But now the Medicines and Healthcare products Regulatory Agency has told Dr Watkins it shares his concerns over the chatbot.
In a letter to the NHS consultant, seen by The Independent, Dr Duncan McPherson, clinical director for devices, said: “Your concerns are all valid and ones that we share.”
The letter followed a meeting with the regulator in October last year. The MHRA is continuing work on a new suite of powers that could include stronger regulation of software apps.
Dr McPherson said new powers that would have seen software like the Bablyon chat bot classed as a medical device were no longer planned to come into force.
He added: “You have raised a complex set of issues and there are several aspects that fall outside of our existing remit. However, this highlights some issues which we are exploring further, and which may be important as we develop a new regulatory framework for medical devices in the UK.
“As we have previously advised you, confidentiality unfortunately binds us from saying more on any specific investigation, but please be assured that your concerns are being taken seriously and if there is action to be taken, then we will.”
In 2018, the MHRA started analysing safety concerns over the chatbot, which was one of the first apps to appear on the NHS app library, in 2017. It was later removed when the NHS opted not to support paid for tools.
Babylon Health, based in London, was recently reported to be exploring a listing on the stock market with a rumoured valuation of $4bn (£2.9bn) according to Bloomberg.
Dr Watkins told the Health Service Journal there was “no quick fix to resolve these issues”, and until a system of “regulatory approval” is in place “we’re reliant on health tech companies behaving responsibly”.
Babylon has partnerships with three NHS trusts, and hosts seven clinics across London and Birmingham under digital GP at Hand service.
A spokesperson for Babylon Health said: "Babylon does not believe that the MHRA has made any public statements about Babylon's product safety or regulatory compliance, nor has it imposed any regulatory penalties."
They added the company complied with the highest safety and regulatory standards and was in the process of applying to get the symptom checker certified under European regulations despite Brexit meaning it was no longer necessary.
It had also passed multiple independent assessments in the last three years.
The spokesperson added: “We believe we’re going further than most other UK digital healthtech companies.
“Babylon continues to be open to interactions with regulators, including the MHRA, and offer our support to any regulator or other body who would like to understand the impact of current and future regulations on companies such as Babylon.”