Green’s Dictionary of Slang

a general term of abuse, denoting a despised, poverty-stricken or otherwise inadequate person.

1887		W.E. Henley ‘Villon’s Good-Night’ in Farmer Musa Pedestris (1896) 174: You bleeding bonnets, pugs, and subs, / You swatchel-coves that pitch and slam.
1998		K. Sampson Awaydays 6: When he’s off the plonk, all boozers are subbies, makes you sluggish [...] etc etc etc.
2000		M. Manning Get Your Cock Out 52: He spent a week or two searching around all the salubrious rock joints in Soho — The Intrepid Rat, The Shit and Shovel [...] The Sub and Mong, the Masturbating Teenager.
2001		K. Sampson Outlaws (ms.) 28: All the subbies from Burnley and Blackpool and that thought it was hilarious.
2024		J. Meades Empty Wigs (t/s) 913: [F]ilthy street-subs. Yucky clothes all piss drip stained, no hair care, face wound, operative scar, scabby sore, all their life possession in rust supermarket trolley.