He offers the analogy of a conveyor belt, on which the individual passes through successive stages: neglected child, disruptive pupil, anti-social teenager, young offender, hardened criminal.

ECONOMIST: Oliver Letwin's big new idea about crime

McKenzie-Jackson and Tulloch will both serve half their sentences at young offender institutions.

BBC: Junior Nkwelle

They have described him as a predatory sex offender and believe he may have abused many people - including young girls - over a 40-year period.

BBC: UK

They have described him as a predatory sex offender and believe he may have sexually abused many people, including young girls, over a 40-year period, sometimes on BBC premises.

BBC: Culture, Media and Sport Committee