In unprecedented "fly on the wall" reporting, New Scotland Yard agreed that a BBC team could shadow the work of the Paedophile Unit, part of the Serious Crime Group of the Metropolitan Police. The result is an important and revealing series. Here is the story and the disturbing detail behind the BBC series. Bob Long has teamed up with DCI Bob McLachlan, Head of the Paedophile Unit, to write a book which everyone who has any contact with children should read. This is not a comfortable read - it is too frank and revealing to be anything but disturbing. But this is because it tells us the truth, and the truth is very hard to bear. Alongside Bob Long's probing analysis as a film-maker and observer, DCI MacLachlan's expert witness describes the subtle work of the police in catching paedophiles. Not only does he show that police methods are highly sophisticated and that paedophiles should beware, but also he gives guidelines for parents and child carers to minimise the risks. Children are too often abused because of ignorance and a lack of discernment. There are simple steps which can be taken to help protect our children.