Green’s Dictionary of Slang

Holborn Hill n.

In phrases

walk (backwards) up Holborn Hill (v.) (also ride (backwards) up Holborn Hill, push the cart up Holborn Hill, ride in a cart up Holborn Hill, sail up Holborn Hill) [the road to Tyburn led from Newgate jail along Holborn. Criminals trad. stood in the cart facing backwards, poss. to increase their ignominy, but more likely to avoid seeing the approaching gallows until the last possible moment]

[early 17C–18C] to go to the gallows.