The idea is important because it will remove insulting and provocatively worded signs from all public places. The threatening nature of the signs is such that they might well constitute an infringement of rights and it is also doubtful if private persons would be allowed or encouraged to display such notices on their land or on their premises. In fact it is unlikely that most private individuals would be so uncouth as to want to produce and publish such crude threats and warnings: so why tolerate this from bureaucrats, police and petty public officials?
The notices are in English; however, they are just as intimidatory to anyone coming through British customs or going into public offices and places. Remove the notices as a matter of urgency and consign them to the same tip as the road signs and motorway clutter.