Here are two definitions of what constitutes an illegal image: The Protection of Children Act 1978, Section 1(1) (a) prohibits the “taking or making” of an indecent photograph or pseudo-photograph of a child. For the purposes of this act a child was defined as being less than 16 years old. The Sexual Offences Act 2003, which came into force on 1 May 2004, amends parts of the Protection of Children Act 1978. "The Protection of Children Act 1978 – meaning of “child” - increased from 16 to 18 years of age."