Police in Britain are investigating children as young as five years old for sexting, according to new data.

Officers spoke to one five-year-old, who lives in County Durham, last year as part of an effort to combat the increasing number of children using phones to send explicit images.

Data uncovered by the BBC found that almost 400 children aged below 12 have been contacted by officers in relation to sexting.

The five-year-old in County Durham was the youngest to be spoken to by the Police, who have also had cases involving four seven-year-olds and four eight-year-olds.

It is illegal to take or send photographs of anybody younger than 18, including yourself.

Northumbria Police told the BBC they had given an official caution to a ten-year-old, who sent an explicit picture of himself to an 11-year-old using a mobile phone app.

However, children younger than 10 cannot be convicted of crimes, as UK law does not deem them capable of being responsible for their actions.

The phenomenon creates a problem for officers, who want to manage the problem without charging and convicting hundreds of children and teenagers.

Steve Thubron, an official with Durham Constabulary, told the BBC that their priority was protecting children, and that officers do not aim to "criminalise" anybody unnecessarily.

Last November, Health Secretary Jeremy Hunt called for underage sexting to be banned completely, prompting complaints from free-speech advocates, and questions from tech experts who wondered whether a ban was even possible.

Some apps have tried to cut down on their own users' sexting as well. In 2015, Snapchat issued new advice to teen users telling them directly to "keep your clothes on!" when communicating with anyone under 18.