preach on Tower Hill, v. — Green’s Dictionary of Slang

preach on Tower Hill v.

[ironic use of SE preach, referring, perhaps, to the criminal’s last words on the scaffold + Tower Hill, the site of many London executions]

to be hanged.

1515–16		Skelton Magnyfycence line 2140: And some fall prechynge at the Toure Hill.
1640		Fortunes tennis-ball 3: But they are mercifull, and still will pray / That great Iove would be pleasd to send a day / That they might hear you preach on tower hill, / Which thing they hope will rid thee from all ill.