If you look at the logo (also to be found at the
The first circle, with an 'i', obviously stands for "Information Booklet".
The second circle, with '999', represents an emergency.
The third circle, with an arrow represents a direction, or "leads to".
The fourth circle, with a keyhole, is obviously John Locke, a C17 philosopher, at least partly responsible for the British (unwritten) constitution.
The fifth circle, with a dial, is to be rotated.
And the last circle, the cross, is an RIP symbol.
So put them all together and the subtext of the terror booklet is:
An Information Booklet about Emergencies that will Lead to John Locke Turning in his Grave.