I've heard you need one for Pimlico so just thought i;d check
1. are you the pope
2. are you a child molesting priest on the run form the authorities hoping to be smuggled in under a nun's habit
3. are you planning to arrive there by parachute drop without going through Italy
If none of the above apply you might wish to carry a passport
You do probably need your head examined all the same.
I liked that bit. Well, I would have had there not been a be crossed army of jobsworths screaming "SSSSIIILENCIO" in everyones faces every three seconds.
Thanksfully I don't speak Italian, so just kept gasping in loud awe.