The regulator said the forum had not done enough to protect UK users – but critics accuse Ofcom of acting too slowly.
A cyber security expert says deleting chat history could lead to a lack of accountability if things go wrong.
The voluntary recall follows an incident on 20 April where an empty Waymo car entered a flooded road in San Antonio, Texas.
Quantexa, a financial data platform, won the £175m contract to spot fraud and tax return errors.
The government said its in-house IT system was “more flexible” while meeting “high standards” of security.
Eben Upton warns against claims that Artificial Intelligence will destroy vast numbers of computing roles over the coming years.
It can take a decade to bring a new orchid to market, so breeders keep their hi-tech processes secret.