Green’s Dictionary of Slang

1. (also bander) soap [rhy. sl.].

1938		L. Ortzen Down Donkey Row 11: Band of Hope – Soap.
1960		J. Franklyn Dict. of Rhy. Sl. 36/1: band of hopeSoap. 20C.
1972		Dodson & Saczek Dict. of Cockney Rhy. Sl.
1981		P. Wright Cockney Dialect and Sl. 103: Band of Hope ‘soap’.
1992		R. Puxley Cockney Rabbit.

2. drugs .

1939

Dly Mirror (London) 2 May 22/1: [cartoon caption] Ah — that’s Soho slang, Jo! ‘Snouty’ means tobacco, ‘River Ouse’ booze [...] and ‘band of hope’ is dope.