I assumed as much. The question was half-rhetorical, though: such regulations did not and could not prevent what happened. There seems to be a law of diminishing returns on regulation: sure, common-sense things like not allowing weapons to mentally ill people go a long way, but increasing regulation past a certain point doesn't reduce problems and only restricts freedom.

So in that case, the question becomes, has the UK already passed that point for internet regulation? I don't know the answer, but I assume that plotting specific attacks or making specific threats online is punishable in the UK just as it is in the US.