OpenAI and Anthropic have promised to take down their AIs if the British secret services show them they are unsafe - activating what some describe as a "kill switch".
Representatives from the two firms told MPs they would respond immediately to evidence of harm from MI5, MI6 or GCHQ, as well as the AI Security Institute (AISI).
"If either AISI or MI5, MI6, GCHQ or any of these authorities came to us and said, 'We think your model is unsafe, we think it's being used by a bad actor', we would obviously look at that immediately with the utmost urgency," said Tom Duff Gordon, head of EMEA policy at OpenAI.
"If we are in control of the model, we would then stop the deployment of that model, or we would pause the training model, or we wouldn't deploy it."
Lord Booth Smith, representing Anthropic, made the same commitment.
"If any agency came forward with demonstrable evidence that the model was not safe or dangerous, we would of course take it off the market," he told MPs at the Business, Innovation, Science and Trade Committee.
However, both men cautioned that they could only do this if they had control of the model, something that isn't always possible.
"There are some nuances with regard to how models in general are deployed because we don't always have control if they're hosted by somebody else," said Mr Duff Gordon.
More from Sky News:
Murder investigation launched into fatal house fire
Failed execution 911 calls released
It comes as the head of MI5 warned that AI is "supercharging" security threats to the UK.
Sir Ken McCallum said: "It can produce propaganda and radicalising material tailored to the individual. We've caught terrorists seeking to exploit AI to improve their reconnaissance and attack methodologies, with AI-enabled drones adding a new twist.
"Not yet realised - but the misuse case to which I'd attach greatest weight - is AI's potential to change the stakes on existing or even new bioweapons."
(c) Sky News 2026: Tech firms promise to take down AI platforms if British secret services show they are unsafe
Man killed by tiger at UK wildlife park pictured
Cancer found after Pope had part of his lung removed during 'successful' surgery
Saudi national charged with allegedly installing a hidden recording device at OpenAI
Brexit result 'not in dispute' despite PM's Russia meddling claim, MI5 chief says
Civil servant 'fraudulently juggled five government jobs using remote work and sick notes'
Cornell University bans frat parties after alleged campus gang rape
Adult victims of arson attack in Waterford which also killed two children are named