Sir Keir Starmer has handed tech companies a three-month ultimatum to introduce device controls to prevent children sending, receiving, or viewing nude images.
Firms such as Apple and Google will face legislation forcing them to activate the tech if they do not comply with the changes by September, the prime minister has warned.
In a speech at London Tech Week, Sir Keir declared that “standing by is not an option”, adding that “the pace of change cannot be an excuse for harm”.
But the prime minister has been urged to go “much further” on the measures, as he was criticised by some political opponents who called his delay in introducing the ban until a leadership contest was on the horizon “desperately sad”.
“One issue is the ability for children with phones to send and receive nude images,” Sir Keir said on Monday. “For too long, people have been told that is simply the price of modern tech, that nothing can be done, that government is powerless, that parents just have to accept it.
“I reject that completely, because tech should adapt to the needs of society, not the other way around.”
He added: “That is why today I am calling on tech companies operating in this country to introduce device controls that prevent children from sending and receiving sexually explicit images.
“Because this is not an impossible challenge. These are some of the most innovative companies in the world and I believe they can solve it. But if they choose not to, then we will act and we will change the law because when it comes to the safety of our children, standing by is not an option.”
The government is seeking to force firms such as Apple and Google to activate built-in features on their devices or come up with technological solutions on phones and tablets to detect and block nude images.
It has called on tech firms to block nudity across the whole device by default, meaning users would have to verify they are older than 18 if they want to take or view such content.
Firms must implement changes within three months or face new legislation, which could lead to fines, and as a last resort, criminal liability for tech bosses.
Former safeguarding minister Jess Phillips resigned from Sir Keir’s government last month, after she claimed he refused to introduce such a law when she presented a solution a year ago because he was “worried about tech bosses”.
She told The Independent the harm she had seen is "unimaginable to most", and said: "I'm glad that the government have announced this, the three month window for Google and Apple to make all device and operating systems block the taking of naked images of children is perfectly possible.
”I will work with the government on the strongest possible legislation backstop that stops children being duped and then groomed by peadophiles to take and send naked images. The harm I have seen is unimaginable to most.”
Sir Keir has faced criticism over his delay in announcing the ban, and the decision not to implement legislation immediately.
Tory leader Kemi Badenoch has said the move is “an idea without a proper plan” and called for children to be removed from social media, while the Lib Dems said it is “desperately sad” that it took so long for Sir Keir to take action.
But Downing Street denied Sir Keir had dragged his heels on the issue, saying the prime minister had “put companies on notice today”.
“It’s important to get this right and that’s why we have been working with the tech industry to do that, and that’s why we’re putting companies on notice today so that either they act within those three months or will legislate to force them,” the prime minister’s official spokesman said.
“But we believe that the companies will want to continue working with us, building on the progress they’ve already made.
“Companies have already taken steps to introduce nudity detection and age verification, so this isn’t a significant ask to see these applied in a way that better protects children.”
Virtually all smartphones sold in the UK either run on Apple or Google operating systems.
Officials said Apple was already taking action with age checks for iPhone users, making it the first company to activate safety features by default for under-18s. But nudity detection is not applied to the camera, third-party messaging apps or search functions.
Home Office officials said they are already working on draft legislation, but would not say how long it might take to become law.
Home Secretary Shabana Mahmood said: “As a society, we have not kept pace with the changing threats that children face. Abuse online is far too common, and we will not tolerate it.
“Tech companies have a moral duty to act, by making it impossible for children to take, share or view nude images. If they don’t, we will legislate.”
