Cameron was answering in response to the following question
> Paul Goggins (Wythenshawe and Sale East) (Lab): Two weeks ago, the head of the Security Service warned about the extent of Islamist extremism. This week, two individuals have been charged with serious terrorist offences. What is the Prime Minister going to do in January when, as a result of his Government’s legislation, some of those whom the Home Secretary has judged to pose the greatest threat to our security are released from the provisions of their terrorism prevention and investigation measures?
> The Prime Minister: We have put in place some of the toughest controls that one can possibly have within a democratic Government, and the TPIMs are obviously one part of that. We have had repeated meetings of the extremism task force—it met again yesterday—setting out a whole series of steps that we will take to counter the extremist narrative, including by blocking online sites. Now that I have the opportunity, let me praise Facebook for yesterday reversing the decision it took about the showing of beheading videos online. We will take all these steps and many more to keep our country safe.
Because of the nature of Prime Minister's Questions, it can't be concluded that this is going to become legislation. It shouldn't be a surprise that the government wants to do, or is talking about doing this.
If you want a particularly nauseating example of the latter phenomenon, look at the question Cameron was asked immediately after the "Islamic extremism" question...
> Paul Goggins (Wythenshawe and Sale East) (Lab): Two weeks ago, the head of the Security Service warned about the extent of Islamist extremism. This week, two individuals have been charged with serious terrorist offences. What is the Prime Minister going to do in January when, as a result of his Government’s legislation, some of those whom the Home Secretary has judged to pose the greatest threat to our security are released from the provisions of their terrorism prevention and investigation measures?
> The Prime Minister: We have put in place some of the toughest controls that one can possibly have within a democratic Government, and the TPIMs are obviously one part of that. We have had repeated meetings of the extremism task force—it met again yesterday—setting out a whole series of steps that we will take to counter the extremist narrative, including by blocking online sites. Now that I have the opportunity, let me praise Facebook for yesterday reversing the decision it took about the showing of beheading videos online. We will take all these steps and many more to keep our country safe.
Because of the nature of Prime Minister's Questions, it can't be concluded that this is going to become legislation. It shouldn't be a surprise that the government wants to do, or is talking about doing this.