Earlier quoted context omitted.
Conspiracy theorist me says we should expect another "act of terrorism" on the UK mainland. This government needs to bolster its control, as they did in Australia, France and Canada. After every attack, the direct effect is that politicians start looking for ways to spin that into invasions of privacy and liberty. Every god damn time. I appreciate that you prefixed this, but are you really implying that the recent at…
Whilst I am not endorsing the view, I would like to point out that Operation Northwoods–style false‐flag attacks are not a necessary reading of the grandparent's post. It would also be satisfied by the government/security services being aware of a planned attack by actual criminals, and simply letting it happen rather than preventing it as would otherwise be done.
I can imagine that the security agencies make mistakes. I can also imagine that they don't always effectively manage and identify the correct intelligence. Whilst blanket surveillance provides you to monitor all the things, it just makes the haystack bigger. Good intelligence and reliable sources on the other hand (which require smart man-power), is costly and laborious. It helps you know in which bale in the haystack you should be taking a closer look at.