the law on male nudity in the UK?

It’s not an offence to be naked in public in England and Wales but it does become an offence if it can be proved the person stripped off with the intention to upset and shock. The complainant has to prove this. In Scottish law there is dick here

‘You owe me’

Even after all this time the sun never says to the earth, ‘You owe me.’ Look what happens with a love like that. It lights the whole sky. Hāfiz (Persian Poet)