Green’s Dictionary of Slang

(Scot. gang) a term of abuse.

1967		A.P. Jephcott Time of One’s Own 132: [graffiti in illus.] Tongs [i.e. a gang name] ya bass.
1968		Daily Tel. 4 Oct. n.p.: Billy, a self-styled founder member of the Tongs, is explaining how the gang was formed: ‘We saw a film The Terror of the Tongs. It was about a Chinese secret society. When we came out we just started breaking windows and shouting: “Tongs! Tongs, ya bass!”’.
1973		(con. mid-1960s) J. Patrick Glasgow Gang Observed 121: Ibsen, ya Bass! [Ibid.] 230: bass, as in ya bass – bastard.
1998		A. Warner Sopranos 49: Fucking bass yon Tina cliped on me that ah was pregnant an they fucking sacked me.
2023		A. Parks To Die in June 31: [T]he legend CUMBIE RULE YA BASS scrawled in black felt pen.