Re: And yet...
I did a bit more reading after posting that. He's recently been prosecuted due to a bespoke ASBO, and ASBOs have very little legal challenge possible. You're not wrong that public nudity is not a straightforward matter.
However, the point is moot, because the latest newspaper article says he's wearing clothes to go walking because his mother is sadly unwell, and he doesn't want to be arrested and therefore not be available to help her.
Biting the hand that feeds IT
