Green’s Dictionary of Slang

(UK Black/drugs) heroin.

2016		1011 Next Up?‘’ 🎵 I put sniff in a rex, and I slang that bobby.
2020		G. Krauze What They Was 34: [D]ark n light which means heroin and crack, or as everyone round here calls it buj and work or brown and white or brandy and champs or Bobby and Whitney.