Ofcom has launched an investigation into Elon Musk’s X over concerns its AI tool Grok is being used to create sexualised images.

In a statement, the UK watchdog said there had been “deeply concerning reports” of the chatbot being used to create and share undressed images of people, as well as “sexualised images of children”.

If found to have broken the law, Ofcom can potentially issue X with a fine of up to 10% of its worldwide revenue or £18 million, whichever is greater.

X referred the BBC to a statement posted by its Safety account at the start of January: “Anyone using or prompting Grok to make illegal content will suffer the same consequences as if they upload illegal content.”.

Elon Musk later said the UK government wanted “any excuse for censorship” in response to a post questioning why other AI platforms were not being looked at.

The BBC has seen several examples of digitally altered images on X, in which women were undressed and put in sexual positions without their consent. One woman said more than 100 sexualised images have been created of her.

If X does not comply, Ofcom can seek a court order to force internet service providers to block access to the site in the UK altogether.

Technology Secretary Liz Kendall told the BBC she welcomed the body’s investigation and urged it to complete it as soon as possible.

“It is vital that Ofcom complete this investigation swiftly because the public – and most importantly the victims – will not accept any delay,” she said.

Kendall’s predecessor Peter Kyle told BBC Breakfast it was “appalling” that Grok had “not been tested appropriately”.

“The fact that I met just yesterday a Jewish woman who has found her image of herself in a bikini outside of Auschwitz being generated by AI and put online made me feel sick to my stomach,” he said.

Other MPs who have raised concerns include Northern Ireland politician Cara Hunter, who said she had decided to leave the platform.

Downing Street meanwhile said the government remains focused on “protecting children” but would keep its presence on X “under review”.

“I think we’ve been clear that all options are on the table,” the Prime Minister’s official spokesperson said.

Ofcom will now examine whether X has failed to take down illegal content quickly when it became aware of it, and taken “appropriate steps” to prevent people in the UK from seeing it.

It said such illegal content included “non-consensual intimate images” and child sexual imagery.

It will also check whether X has used “highly effective age assurance” measures to stop children from seeing pornographic images.

The decision follows global backlash over Grok’s image creation feature, with both Malaysia and Indonesia temporarily blocking access to the tool over the weekend.

An Ofcom spokesperson did not give an indication on how long the investigation would take but said it would be a “matter of the highest priority”.

“Platforms must protect people in the UK from content that’s illegal in the UK,” they said.

“We won’t hesitate to investigate where we suspect companies are failing in their duties, especially where there’s a risk of harm to children.”

Lorna Woods, professor of internet law at Essex University, told the BBC it was “hard to predict” how quickly the investigation would move.

“Ofcom has a degree of choice in how fast – or slow – they take the investigation,” she said.

She said the regulator could apply for a business disruption order – a court order to block access to X in the UK – straight away rather than as a last resort, but only in “rare circumstances” in response to an ongoing problem.