You are in a British pub and you need to answer the call of nature! What do you ask for?
Which door do you go into? Asking for the loo is a friendly and fairly polite British way of saying toilet, a word that natives often prefer not to use.
Loo is probably the safest word to use in most situations in Britain, either in public places or private homes. Both words also refer to the receptacle that you find in the bathroom. This is a problematic area in English, as there are so many words that can refer, in different ways, to the same thing.
You might sound a little strange asking for the bathroom in a pub, as there is no bath, but it is perfectly acceptable in someone’s house.
The word W.C. is very old fashioned and not used (except in Spain and Italy!).
Similarly little boy’s room and women’s powder room, which sound Victorian.
Restroom is polite, socially acceptable, but will make you sound like an American tourist.
The john and the can are also American, but are very colloquial and are considered quite vulgar or low class.
The dunny is a comical Australian way of expressing the same idea.
The bog and the crapper are very crude slang words in Britain, not to be used in good company.
Other things that you might find on the doors of public toilets in bars are the letters G and L Which one would you enter? G means Gentlemen (sometimes written as Gents), and L means Ladies. You might also find his and hers, guys and gals, or even as John and Jane.