On 03 November 1783 the last execution by public hanging took place at the Tyburn Tree gallows near where Marble Arch is today, when John Austin was put to death for murdering John Spicer. Executions moved to Newgate Prison, so the spectacle of having criminals paraded in a cart along Oxford Street to the gallows, which had been going on for hundreds of years, ended.
These parades went all the way back to the 12th century, and plenty of Catholics were martyred at Tyburn Tree in the years of Protestant reprisals against the regime of Bloody Mary. The trip to the gallows would take hours because of the crowds enjoying the slaughter.
There are markers and memorials at a few spots still visible today; more info here:
https://marble-arch.london/culture-blog/history-of-tyburn-tree/?