Except daemon, if we assume the man is guilty then this amounts to coercion to a confession does it not?
Are you telling me you would not admit to practically any crime for fear of being sent to jail under the title "paedophile" ?
Do you want a justice system where people are forced to admit guilt (regardless of guilt) or be sentenced to the same or worse punishment anyway.
It has been proven time and time again the uk penal system is incapable of protecting those in it's custody, and as such it is better 100 guilty men go free than one innocent man be sentenced.
This is one of the problems, you aren't understanding it correctly, he isn't being charged or assumed guilty of Child Porn, he's actually sent to jail for what is effectively obstructing the course of Justice.
Same as with the suspected drink driver, he isn't accused/sentenced for drink driving if he doesn't provide a sample, he's done for the separate crime of 'failing to provide a specimen'.
It's funny you and others hold the UK Penal system in such contempt, because in the case of the big ol' world, it's actually one of the better ones..
At the end of the day, any 'system' only has so much resource, but a huge expectation, it is inevitable that some wrongful convictions occur, society is not tolerant of that either, which is why it has to always been as low as possible, but it'll never be zero, that's untenable.
On top of that, people seem to be confusing wrongful arrest (quite common) with wrongful conviction (quite rare, but it does happen).
If the goal was zero wrongful convictions, one of two things would occur
1. There'd be a huge increase in crime, believe it or not, criminals are quite sneaky and have a plethora of get out clauses that can conveniently be used
2. You'd have to pay a massive amount more in taxes, and give up some freedoms in order to maintain the crime rate conviction levels.
So which is it? There isn't some golden panacea that gives you zero wrongful convictions + low crime without some serious compromise..