Holborn Hill (Grose 1811 Dictionary)

To ride backwards up Holborn hill; to go to the gallows: the way to Tyburn, the place of execution for criminals condemned in London, was up that hill. Criminals going to suffer, always ride backwards, as some conceive to increase the ignominy, but more probably to prevent them being shocked with a distant view of the gallows; as, in amputations, surgeons conceal the instruments with which they are going to operate. The last execution at Tyburn, and consequently of this procession, was in the year 1784, since which the criminals have been executed near Newgate