The term "what the...." was invented for comments such as these from Scotland's Crown Office and Procurator Fiscal Service and quoted by The Register:
"We do not publicly disclose our prosecution policy in relation to specific offences as to do so may allow offenders to adapt or restrict their behaviour to conduct which falls short of our prosecution threshold."
So we're no going to tell you what is and is not illegal just in case you stick to the stuff that is legal? Indeed the Procurator went on to say that Freedom of Information requests wouldn't help as such information is exempt.
OK this is about 'extreme pornography' where there's a very sound case for controls but surely the Government should set out some guidance as to what it does and does not consider to be 'extreme'?