Child sexual abuse in the United Kingdom has been reported in the country throughout its history. In about 90% of cases the abuser is a person known to the child. However, cases during the second half of the twentieth century, involving religious institutions, schools, popular entertainers, politicians, military personnel, and other officials, have been revealed and widely publicised since the beginning of the twenty-first century. Child sexual abuse rings in numerous towns and cities across the UK have also drawn considerable attention. In 2012, celebrity Jimmy Savile was posthumously identified as having been a predatory child sexual abuser for the previous six decades. Subsequent investigations, including those of Operation Yewtree, led to the conviction of several prominent "household names" in the media, allegations against prominent politicians, and calls for a public inquiry to establish what had been known by those responsible for the institutions where abuse had taken place. An Independent Inquiry into Child Sexual Abuse was announced by the British Home Secretary, Theresa May, in July 2014, to examine how the country's institutions have handled their duty of care to protect children from sexual abuse. Categories of child sexual abuse The Child Exploitation and Online Protection Command identify four broad categories of child sexual abuse in the United Kingdom, which they describe as the four "key threats" to children. The proliferation of indecent images of children – particularly the production of still, moving and live-streaming of child abuse images. Live streaming of abuse of third world children for consumption by UK paedophiles is increasing. Perpetrators are being increasingly found and brought to justice. Tracking down and safeguarding third world child victims is more difficult. There are calls for better funding for the National Crime Agency so these crimes can more easily be prevented. Online child sexual exploitation – with a focus on the systematic sexual exploitation of multiple child victims on the internet. Transnational child sexual abuse – including both transient and resident UK nationals and British citizens committing sexual offences abroad. Contact child sexual abuse – particularly the threat posed by organised crime-associated child sexual exploitation and the risks around missing children. Within this category there are a number of recognised types. Firstly, contact child sexual abuse by lone offenders. Secondly, contact child sexual abuse by group offenders and offending associated with street gangs, of which there are two types. Type 1: Group offending targeting victim vulnerability. This