As reported in the Channel M video below (via Boing-Boing), Manchester police arrested Stephen Clarke and detained him for 2 days for apparently photographing a drain cover with his mobile phone. After searching his home and belongings he was eventually released without charge, although his fingerprints and DNA were retained.
It appears police are now in the habit of 'sealing' drain covers for security purposes, presumably to deter the insertion of explosives or Jihadist lunatics using them as foxholes, or possibly scary Wild Things escaping and biting passers-by. Unfortunately the seals are a novelty yet public nosiness about them appears to indicate hostile reconnaisance to the police rather than 'what's that all about then?' curiosity. The shortcomings of this police logic are so hideously obvious that we suspect the real intention is to try and stop citizens escaping from this increasingly bonkers police state via the sewer network.