Pupils should be banned from taking smartphones into school, the minister for school standards in England has told the BBC.
Nick Gibb spoke out ahead of the government publishing new guidance for schools, expected to address internet safety, social media and online gaming.
It is expected to say children should be taught to limit the amount of time they spend online.
Schools have the power to ban phones from being taken on to the premises.
But government policy is that it is the responsibility of head teachers to determine whether this is appropriate.