St. George said "It's actually a lavatory, use of the word toilet does nothing for ones social standing!"
In descending order from Posh to Slob. UK English
Where is the Ladies/Gents lavatory, please? (Formal)
Where's the Loo? (Less Formal, more genteel than the next one down.)
Where are the toilets/gents/ladies? (Normal everyday use)
I'm off to the bog. (Mainly a male comment - perhaps camping with mates/working on a building site)
I'm busting for a dump! Where's the bog? (Freddo - in urgent need)
I need the crapper/shitter. (What Freddo really means)
Hope that helps!