Proof that the option appears:
Of course you can not do this if you are not a UK resident as the EULA says, but you already knew that, right?
Sadly, “None” doesn’t exist as an option anymore: http://skitch.com/jacobbotter/n2itr/itunes
It still works – I just tested it.
Go to iTunes Store > Log out of existing account > Change to the UK store > Find Spotify (or any free app) > Click “Free” to buy > Plot in new email and pass > Click “Continue” > You have the “None”-option.
I think it’s a way for parents to create an account for their children where they can download any free app they want, but not paid ones.
Ofcourse I just didn’t pay attention to step 2, also see http://support.apple.com/kb/HT2534