Green’s Dictionary of Slang

the world of street prostitution, esp. as phr. on the bash, working as a street-walker.

1937		R. Westerby Wide Boys Never Work (1938) 117: Girls like that, girls who went on the bash every night like she did.
1938		G. Kersh Night and the City 88: Anybody would think I was asking you to go on the bash.
1946		G. Kersh Nigth and the City 122: Anybody would think I was asking you to go on the bash, or something. You can keep respectable in a night club.
1946		S. Jackson Indiscreet Guide to Soho 30: He’s a waiter, like me, but lucky. Got a girl who goes out ‘on the bash’ for him.
1958		(con. 1940s) B. Behan Borstal Boy 304: Loosening ’er drawers to go off down the town, on the bash.
1959		F. Norman Fings II i: I’ve seen worse than ’er on the bash.
1959		B. Naughton ‘The Little Welsh Girl’ in Late Night on Watling Street (1969) 144: We could have sent her out on the bash ourselves.
1962		F. Norman Guntz 57: Just because a few geezers in Parliament don’t want the girls on the bash no more.
1963		F. Norman in Show Jan. in Norman’s London (1969) 1443: They take the birds orf the bash [...] and then expect them to settle darhn and get job in offices and that.
1967		T. Parker Women in Crime 75: Well when I come out [of prison] I’ll have nothing, so the quickest way to get a bit of money is to go on the bash for it.
1986–7		Maledicta IX 144: They slip into [...] kit that shows off the merchandise and walk about on the bash, casually looking.