Under British law it is legal to have sex aged 16, but it is illegal and a serious criminal offence to take, hold or share 'indecent' photos of anyone aged under 18.
It is a crime to:
•take an indecent photograph or allow an indecent photograph to be taken
•make an indecent photograph (this includes downloading or opening an image that has been sent via email)
•distribute or show such an image
•possess with the intention of distributing images
•advertise