You cannot introduce a weakness into a security product and expect it to only be exploitable by yourself, Mr Cameron.
Arriving at the conclusion that “it is currently not appropriate to adopt restrictive legal measures against the development, availability and use of encryption” within the Netherlands, van der Steur shows that he gets how backdoors would make encrypted data vulnerable to not only criminals and foreign intelligence services but, yes, also to the very terrorists that Cameron and his cohorts argue they would protect us from. Backdoor access is, simply put, not a one-way street. You cannot introduce such a weakness into a security product and expect it to only be exploitable by yourself. Well, Cameron obviously does expect exactly that, which means that he’s either an idiot or has been getting very poor technical advice: most likely a bit of both, if you ask me.