Officers in Cumbria are warning parents to be alert to signs of internet bullying over the summer holidays and to learn more about what their children are doing online.
Online threats are the biggest risk, but the police are also concerned about an increase in teenagers texting pornographic images.
The warning came as the Prime Minister said Britain had to do more to protect childhood innocence.
Dan Ashby reports:
More top news
London Mayor Sadiq Khan's comments on Scottish nationalism prompted a fierce response from Scottish First Minister Nicola Sturgeon
Police in the Borders are warning the public to be vigilant following reports of bogus workmen operating in the Tweedbank area.
What weather will dominate this weekend?