Excellent idea, let's make the best use of our recession-hit resources. May I also suggest that we could train these pigeons to poo on:

a. Any dog pooping on the streets of SE23. Poo the poopers.

b. The new Domino's delivery mopeds in HOP. (special stage II training of pigeons required for the task, we don't want them to accidentally hit say the parked car of an estate agent or the Honor Oak Guitar Man while he's belting out his favourite tune at the station entrance)

c. Any common criminal, benefit fraud or general lowlife deemed fit to stand trial and be convicted by Brian (special stage III training of pigeons plus a C&G required for this task, only the most clever pigeons may be selected for this). Why waste taxpayer's money on old-fashioned methods such as caning, stoning or public execution (clearly favoured by certain sections of the SE23 forum), when this is so much cheaper.

(ok, back to work then, clearly too much time on my hands today...)