From http://www.actionfraud.police.uk/ we see:-
Well, obviously the Royal Mail need a default opt-in adult content filtering in place for this - it is just not good enough - my kids could open the post unsupervised and play these DVDs. They should open every parcel and letter and check it is not porn in there. Why is the Royal Mail allowing this? I did not opt-in for the porn version of post did I? The government need to force all postal carriers to filter the mail NOW!!!!
OK, Daily Mail mode off now...
I wonder why this is happening - perhaps someone is trying to make a point. It wasn't me, honest!