Green’s Dictionary of Slang

1. a metropolis; usu. London.

1914		Ade ‘The New Fable of the Aerial Performer’ in Ade’s Fables 194: The gallus Offspring hurried to the Metrop to pick the Primroses.
1914		Truth (Melbourne) 31 Jan. 6/3: Now it’s all over and I’m back in the noisy metrop [i.e. Brisbane].
1919		Wodehouse ‘Aunt and the Sluggard’ in My Man Jeeves [ebook] [of New York City] [B]y Jove, you know, dear old Rocky made him look like a publicity agent for the old metrop!
1923		Wodehouse Inimitable Jeeves 194: They must not wander at large about the metrop.

2. (Aus.) as adj. metropolitan.

1996

J. Byrell Lairs, Urgers & Coat-Tuggers 302: [H]e starts going to every Sydney metrop meeting he can find time for.