A new smartphone for children will automatically block nudity and sexual content from being seen, created or shared with the device.

The HMD Fuse has a built-in “HarmBlock” AI feature that detects explicit content directly on the device. Developed by the British company SafeToNet, HarmBlock is embedded in the phone’s operating system, meaning there’s no setup required and it cannot be removed like a standard app.

HarmBlock worked with 90 per cent accuracy in real-world test conditions, according to SafeToNet. The phone has been developed by Human Mobile Devices (HMD), which makes Nokia devices.

HMD has started the Better Phone Project, a collaboration with parents to develop more child-friendly smartphones. It has already released a similar phone called the Fusion X1.

The Fuse comes out of the box as a “brick phone” with calls, texts and location tracking, but parents can release more functions over time as the child gets older. More child-friendly devices are coming on the market as parents become more concerned about the impact of smartphones. Others include the Pinwheel and Sage phones.

On Monday, Dame Rachel de Souza, the children’s commissioner, warned about the growing number of youngsters accessing pornography, saying that children as young as six are finding adult content.

She urged the government to stop under-18s using specialised software that avoids checks on porn sites by clamping down on virtual private networks, which enable users to skirt around new age verification rules.

HMD Fusion X1 kids' smartphone.

The Fusion X1, an earlier child-friendly smartphone developed by HMD, designed with built-in safety features and parental controls aimed at younger users

One in five secondary school-aged children has felt pressured into sharing an explicit image of themselves, according to a survey from Vodafone.

The research also showed that 41 per cent of teachers reported explicit image-sharing as a growing problem in their school. More than one in four teachers said that they dealt with at least one incident of explicit images of students being shared by other students in the last academic year.

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Richard Pursey, chief executive of SafeToNet, said: “HarmBlock AI brings a new dimension to our parental controls technologies as it focuses on harmful content, as opposed to simply remotely managing a device and the apps running on it. By embedding HarmBlock and parental controls in the operating system, we have made devices safer, irrespective of the apps running on it. That is ground-breaking.”

James Robinson, vice-president of HMD, said: “The HMD Fuse protected with HarmBlock addresses parents and children’s collective concerns about device access and online safety. It gives parents more control and peace of mind and helps to protect children from explicit content in real time, without encroaching on their privacy.”

The Fuse is available through Vodafone for £33 per month with a £30 upfront cost.