Green’s Dictionary of Slang

1. (Aus.) a scab, a non-unionist [= scab n.¹ (4)].

2002

Pete’s Aussie Sl. Home Page 🌐 hansom cab: a scab, a non-unionist.

2. (also hanson cab) a body louse [= SE crab, a louse].

1978

Maledicta II:1+2 (Summer/Winter) 118: He [...] also lists: [...] Hanson Cabs Crabs.