The law relating to child pornography in the United Kingdom has, over recent years, changed dramatically. These changes have been brought about by both legislation and case law. This article critically analyses the consequences of these changes and, in particular, considers the probity of apparent reverse burdens of proof created by the legislation. When the right to a fair trial is being examined, it is usual to balance the rights of the individual defendant and the rights of society to expect a smooth-running criminal justice system. The balancing act in this field is more complicated because those who are the subject of abusive images are the most vulnerable members of society, and thus the balance struck must not unduly constrain law enforcement agencies, preventing them from tackling the exploitation and abuse of children.