blucher, n. — Green’s Dictionary of Slang

blucher n.

[proper name of Field-Marshal von Blücher (1742–1819). According to the Social Science Review (vol. I, 1864), the cabs were ‘named after the Prussian Field Marshal who arrived on the field of Waterloo only to do the work that chanced to be undone’]

an ‘outsider’ cab that is forbidden to enter the London railway termini.

1889		Clarkson & Richardson Police! 249: Non-privileged cabmen are termed ‘Bluchers’.
1890–1904		Farmer & Henley Sl. and Its Analogues.