Slip-slop, wish-wash, twaddle, talk about gruel. “Skilly” is prison-gruel or, more strictly speaking, the water in which meat has been boiled thickened with oatmeal. Broth served on board the hulks to convicts is called skilly.
“It is the policy of Cursitor Street and skilly golee.” —The Daily Telegraph.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894