I always find it pays to read Cameron's speeches as well as listening to them. When I listen I usually think he is on the right track, when I read them not so. This one is no exception. Cameron uses the phrase "let me be clear" in the way a dishonest car salesman says "to be honest." Just as you might expect to hear "To be honest, 80s Alfa Romeos don't really rust" from the car salesman, David Cameron's insistence on "being clear" liberally peppered a speech which was anything but.
What sounded like aggressively promoting British liberal and democratic values actually reads as though he simply intends to apply more of the same. Extra state snooping powers, increasing recruitment of minority groups to the police and other public bodies, religion-of-peace type platitudes - though he is far too shrewd to use the actual term which has become impossible to say without irony.
What about the flip side of a successful liberal society which is a firm embrace of the idea of consequences. The near certainty that if you do A, B, C then X, Y and Z will follow, as sure as night follows day. If you're caught going to fight for an enemy state then your British citizenship is revoked. If you're caught using public institutions to promote your personal or religious cause then you will be treated as a serious criminal and face a hefty gaol term. If you are dishing out barbaric violence for any reason whatsoever then you will be punished to the full extent of the law.
These things don't even need to specifically target Islam. They are the underpinnings of a free society because without them people are not free, unless they are powerful enough to know they can escape the consequences of their wrong-doing.