Latrine! Of Course! The hideous creature that lives in the North Tower and performs magic for me!

OOPS! Sorry: that was a paraphrase / quote from "Robin Hood: Men In Tights"

I knew there was a term escaping me. As you've workes in a military museum, I shall have to bow to your knowledge. However, my own dad tends to call "the smallest room" the "Lav" and he picked up the term from his dad who adopted the saying after 3 and a half years (almost full time) on the Western Front where he was stationed with the 'KIngs Own Scottish Borderers'; be fore that, apparently he and his brothers (who all served in WW1 in various Scottish Regiments) all used to refer to the toilet as "The Wee Hoose" (no puns intended). However, after the war, the six that survived all universally called it "The Lav" or "The Lavvie".

I'm not 100% on this next bit, but I have an itch in my 'memory gland' that latrine is actually also etymologically linked with lavatory as well. Not sure here though.

Oh, and BTW - my grandad wasn't the non-survivor of the Great War; Not sure which one of his brothers it was - he was, however gassed 3 times which left his lungs and heart a mess and ultimately killed him in 1960 at age 62. Not bad for a man whose wife was told "don't marry this man - he won't live beyond 30" by the doctors. The family always said it was Granny's nursing and care that kept him alive tose extra 32 years. He also had one brother who was badly gassed (once) and died younger than the others as well - the other four brothers all lived well into their nineties.

Muttley