The government proposals have been welcomed by organisations and charities calling for tougher measures and technical solutions to stop children from not just seeing, but also capturing and sharing nudity on smartphones.

Ofcom data suggests that a growing proportion of younger children in the UK own a smartphone - and that the number of those do increases with age.

According to children's charity the NSPCC, content filmed on a child's device can be the starting point for grooming, sexual extortion and other forms of online child sexual abuse.

UK police chiefs have previously said restricting the ability of children's devices to take or share nude images would be a key step in preventing sextortion - crimes where a child is groomed into sharing explicit images and blackmailed.

Chris Sherwood, NSPCC chief executive, said legislative plans were a "necessary move" after tech firms failed to meet the three-month deadline.

But he said "children cannot face more delays, so Government must act swiftly and ensure these measures are enshrined in law at the earliest opportunity".

Andy Burrows of the Molly Rose Foundation said while the new proposals were "fundamental to their objective", it had been "a needlessly long and torturous road" to secure them.

"Ministers will need to demonstrate they are committed to delivering robust legislation without further delay," Burrows added.

Government proposals to prevent nude images being shared taken and shared by children were originally proposed as part of the government's violence against women and girls strategy.

But it faced criticism within its own ranks for being slow to enact it.

Its plans for a new law to enforce the measure would not prevent adults from accessing naked imagery on their device.

However, implementing solutions to block it for children may require checking whether the user of a phone, or app, is an adult or a child.

Online rights campaigners at the Open Rights Group have previously warned that implementing the change would mean "every adult would be forced through a digital ID checkpoint, and private images could be scanned by default".

The government has denied that the move would amount to surveillance.