Green’s Dictionary of Slang

1. see snitcher n.² (2)

2. a confidence trickster [one who switches ‘good’ things for ‘bad’ ones].

1822		Egan Life and Adventures of Samuel Hayward 3: Recently we have had the life of david haggart, (alias the Switcher,) written by himself, while under sentence of death, [...] he was executed at Edinburgh, July 18, 1821. Haggart was only twenty years of age.
1846		Swell’s Night Guide 61: gonniff: Nix my schickster; do you see anything green about me? cos I doesn’t! its no bite my switcher, do you stag that? – walker!