From Preparing for emergencies

Page 14:

“To prepare for an emergency, you should take time to find out: […]

  • The emergency procedures for your children at school
  • The emergency procedures at your workplace”

Page 16:

“If you hear, see, or come across anything that may be linked with terrorist activity, please tell the police.
[…]
Have you seen anyone pay an unusual amount of attention to security measures at any location?”

So, report anyone you see reading PfE to the police. If they have nothing to hide, they have nothing to fear.

(No, don’t report me, I got this from ForeverDirt)

Stay alert, troubleshooters.