The UK government says Elon Musk’s platform X limiting Grok AI image edits to paid users is “insulting” to victims of misogyny and sexual violence.

Speaking on Friday, Downing Street said the move “simply turns an AI feature that allows the creation of unlawful images into a premium service”.

It follows significant backlash after Grok digitally altered images of others by undressing them – something it says it now can only do for those who pay a monthly fee.

But the prime minister’s official spokesperson told reporters on Friday it showed X – which has not yet commented – “can move swiftly when it wants to do so”.

The BBC has approached X for comment.

The prime minister was “abundantly clear that X needs to act and needs to act now”, his spokesperson said.

“It is time for X to grip this issue, if another media company had billboards in town centres showing unlawful images, it would act immediately to take them down or face public backlash,” they added.

But while Grok will only alter images on X for those who pay, it has no such restriction when accessed through its separate app and website.

The Liberal Democrats have called for access to X to be temporarily restricted in the UK while the social media site is investigated.

“Musk has thrown his toys out of the pram in protest at being held to account for the tsunami of abuse,” said Professor Clare McGlynn, an expert in the legal regulation of pornography, sexual violence and online abuse.

“Instead of taking the responsible steps to ensure Grok could not be used for abusive purposes, it has withdrawn access for the vast majority of users.”

And Hannah Swirsky, head of policy at the Internet Watch Foundation, said it “does not undo the harm which has been done”.

“We do not believe it is good enough to simply limit access to a tool which should never have had the capacity to create the kind of imagery we have seen in recent days,” she said.

The charity previously said its analysts had discovered “criminal imagery” of girls aged between 11 and 13 which “appeared to have been created” using Grok.

“Sitting and waiting for unsafe products to be abused before taking action is unacceptable,” Swirsky said.

Grok is a free tool which users can tag directly in posts or replies under other users’ posts to ask it for a particular response.

But the feature has also allowed people to request it to edit images – and ask it to digitally strip people of most of their clothing.

Grok has fulfilled many user requests asking it to edit images of women to show them in bikinis or little clothing – something those subject to such requests have told the BBC left them feeling “humiliated” and “dehumanised“.

However as of Friday morning, Grok has told users asking it to alter images uploaded to X that “image generation and editing are currently limited to paying subscribers”.

It adds users “can subscribe to unlock these features”.

Some posts on the platform seen by BBC News suggest only those with a blue tick “verified” mark – exclusive to X’s paid subscriber tier – were able to successfully request image edits to Grok.

Dr Daisy Dixon, a lecturer in philosophy at Cardiff University and female X user who said she had seen an increase in people using Grok to undress her, welcomed the change but said it felt “like a sticking plaster”.

“Grok needs to be totally redesigned and have built-in ethical guardrails to prevent this from ever happening again,” she told the BBC.

“Elon Musk also needs to acknowledge this for what it is – yet another instance of gender-based violation.”

Prof McGlynn said X’s move echoed its approach to pornographic Taylor Swift deepfakes on the platform last year – where it blocked searches for sexualised material generated of the popstar using a Grok AI video feature.

“He is doing this to stoke free speech arguments,” she added.

“He will claim regulation is stifling people’s use of this technology. But, all the regulation requires is that he takes necessary precautions to reduce harm.”

Ofcom’s powers under the Online Safety Act include being able to seek a court order to prevent third parties from helping the Elon Musk-owned platform raise money or be accessed in the UK.

The BBC has approached the regulator for comment.

Lib Dem frontbenchers Victoria Collins, Marie Goldman and Max Wilkinson have written to Ofcom boss Dame Melanie Dawes, asking her to take action.

“If any other platform were found to be facilitating the mass generation of sexual abuse imagery at this scale, it is difficult to believe it would be permitted to continue operating uninterrupted,” they wrote.

“Ofcom must restrict access to X now while an investigation takes place.”

Downing Street reiterated the government’s “full support” for regulator Ofcom to use all its powers – up to and including a ban.

Prime Minister Sir Keir Starmer previously called images generated by Grok “disgraceful” and “disgusting”.

Meanwhile the Conservatives reiterated comments made following PMQs on Wednesday by a spokesperson for Kemi Badenoch, who called deepfake images “absolutely abhorrent”.