The number of sexting cases involving children has more than doubled in two years, police figures have suggested, leading a senior officer to warn about deficiencies in proper sex education.

Simon Bailey, the National Police Chiefs Council’s lead officer on child protection also raised concerns about extreme pornography being shared among young people, and social media sites acting quickly to take down such material.

He spoke as police forces in England and Wales released data on Monday showing they registered 6,238 sexting offences in 2016/17 – a rate of 17 every day. That represented an increase of a third on the tally of 4,681 in the previous year and of 131% on 2014/15, when 2,700 cases were logged.

“There is a worrying upward trend in children sharing sexual images, particularly regarding children who pass on indecent images of others. Sharing and possessing these images is against the law. Once an image is shared with others it can cause deep embarrassment and distress,” said Bailey.

“I am concerned about the impact that exposure to extreme pornography can have on children so we need to consider if a lack of universal relationship and sex education is compounding the problem.

“There is also undoubtedly more to be done to remove indecent imagery quickly and robustly from across social media platforms once it has been shared or posted without consent.”

The data relates to recorded offences involving indecent or prohibited images of children, where the suspect or offender is younger than 18 years old. Police said reports come from children as young as 10, with cases peaking around the age of 14.

Boys are as likely as girls to be recorded as suspects or perpetrators but girls are more likely to be recorded as victims, according to the data. They also appear to show a substantial decrease in cases during the month of August, coinciding with the school holidays.

The trend for sharing explicit images among youngsters has emerged as a challenging issue for authorities amid fears that children and teenagers could be routinely criminalised over the behaviour.

Last year, the Home Office introduced a new outcome in crime recording rules, which allows forces to log an offence without any formal action being taken as it is not in the public interest. The outcome can only be used in cases where there is no evidence of exploitation or malicious intent.

Initial analysis indicates the number of children facing charges in these cases has more than halved, with the newly created outcome used more than 2,000 times in 2016/17.

“Forces are risk assessing every case to ensure we are not unnecessarily stigmatising children and saddling them with a criminal record,” said Bailey, who is also the chief constable of Norfolk police.

“But there will always be a criminal investigation where we see that young people are being coerced, exploited or blackmailed.”

The NSPCC said the rise in sexting incidents was “extremely worrying”, adding: “It is vital that parents and schools talk to children about the dangers of sexting as soon as they are given any technology.”