This is what happens when politicians don't consult experts in the field about how crime rings operate on the internet. If they honestly believe paedophiles, terrorists and whom ever else is just going to blatantly do their thing without going behind a few encrypted proxy servers then it is them who deserve to be in prison.
When I worked for a government service company which provides internet access to schools in a certain area of the UK, I made a case report showing just how easy it was for a child with very little knowledge to bypass ALL of their online filtering, security and monitoring services with a simple free proxy site. I then followed on to show them how even with the most sophisticated monitoring hardware AND software, it is still IMPOSSIBLE to track the online movements of a person who is intentionally evading these technologies.
For less than £30 a month I purchased eight 256bit SSL encrypted proxies around the world, each of which would make a random connection to each other in a random order for each unique TCP stream. In doing this, even tracing the TCP/IP connections was impossible due to international laws (It can take years for a court to get records from another country/government). All of these servers also kept all records on drives which where sanitised every half hour and restored from a clean backup (restores took less than 1 minute), so even if one of the servers was located simply trying to get any meaningful data from it was fruitless, not to mention it was all encrypted anyway.
Then there is the plain simple form of online criminal communications which is in plain site on forums just like this one in which users communicate using what looks to be normal chatter. For instance, would you be suspicious if some guys where chatting on here about joining up for jogging sessions? In reality those guys could very well have pre-arranged to use the forum and that topic to communicate about when they want to have sex with children and where.
In reality the only reason this law has been passed is because the fat cats at Warner Bro's (Etc) can't afford to buy a new yacht this year and are kicking up a stink over in the USA, where most of the politicians have massive amounts of capital invested in the media industry. And with Mr Cameron being bum pals with Obama and sharing a common agenda for "Defeating Terrorism" we simply follow suit without question.
As for this petition, it's never going to work. There have been petitions go through parliament with hundreds of thousands of e-signatures and they haven't even been sniffed at.