Pointless bureaucracy
I got chatting to an immigration lawyer at the weekend (friend of a friend) who told me that the whole thing is a futile waste of time and money.
The Home Office identifies citizens of EU Member States (who are actually entitled to be here) who are 'homeless' (as defined) and serves them papers asking them to leave the country or else they'll be deported.
Half of them ignore it, homeless foreigners being notoriously difficult to track down, and half of them fill in a 137-page form (I think he was exaggerating a bit ...