http://www.tom-watson.co.uk/wp-content/uploads/2013/01/d-notice.jpg

I don't doubt at all that D-Notices are not used to protect criminal activity. I'm aware it's voluntary to comply and in a way happy to see this minimal protection anyway, not just for security/working government concerns but also to see that genuinely innocent people are not destroyed by the accusation - any safety net with false allegations is probably welcomed by us all.

There is a way to create new evidence, setup a website to crowd-source for victims who know their attacker and use a 'no-names' '20 questions' approach similar to the game 'guess who'. Repeat offenders get identified quite quickly this way. I built a prototype like this for victims of rapists - just looking for ways to help crime really. It's possible, we are in the age of data scientists now.

There was a case study I found earlier today regarding Don Hale, a newspaper editor who in the early 80's investigated a story around child abuse of known figures. He was given D-notice in the presence of a large group of uniformed and non-uniformed police. They wre seemingly more interested in taking 'all copies' of notes and supporting story bits with intimidation/threat of arrest for perverting the course of justice - which works well on a man with a family to support. If it was an investigation, then a copy of the info would have done, if the D-notice was portrayed as voluntary - why the persuasion and over-whelming force. This didn't seem right, other investigators of this have found an official response that no D-notice existed - it was likely they did not represent official channels. So this means there is a group of people who dress like police who use d-notice props to take evidence of criminal activity related to this. It's not the only case I found in Google. Sounds a bit like we have a rouge spook-sounding element that has felt the need to protect some interests which has negatively effected legal due process for real crime. I hope 'why' is recorded for historic record somewhere and it was actually UK officials acting for a higher purpose. So I'm done looking into this now, satisfied that all these mixed messages and impressions are because of some third party interest acting independently, dressed as legal channels but acting beyond the power and interests of their costumes.