Green’s Dictionary of Slang

(UK Und.) highway robbery by footpads (rather than mounted highwaymen); thus the low-toby lay, street robbery.

1812		Vaux Vocab. of the Flash Lang. in McLachlan (1964) 274: The toby applies exclusively to robbing on horseback; the practice of footpad robbery being properly called the spice, though it is common to distinguish the former by the title of high-toby, and the latter of low-toby.
1823		‘Jon Bee’ Dict. of the Turf, the Ring, the Chase, etc. 176: Low toby-lay ? foot-pad robbery.
1824		Sir W. Scott St Ronan’s Well (1833) 337: We have already had footpad work enough—I promise you the old buck was armed, as if he meant to bing folks on the low toby.
1872		Falkirk Herald 27 Apr. 4/6: Holloway [...] asked if he had any objection to being in on a good thing, It was to be a ‘low toby’.