The weather was pleasant for the 1820 fair, attracting large crowds, along with pickpockets. An officer, when alerted to a robbery, declined to intervene, stating that he was there for leisure and not on duty.

Crime was prevalent. A gold watch and chain belonging to Miss C. were snatched but later recovered. In a refreshment booth, a man was severely attacked by a group when he attempted to stop them from robbing him of £4. Large gangs, consisting of around 30 to 40 individuals, roamed the area in the evening, robbing people indiscriminately. Some gentlemen organised a group to confront the gangs but were attacked with lead-weighted clubs. Many chose to remain overnight, fearing robbery on the dark roads. It was rumoured that many pickpockets originated from the West End.

Individuals returning to town via Mile End Turnpike were stopped and required to uncover and swear allegiance to the Queen. Two men in a gig attempted to drive rapidly through a barricade, resulting in the vehicle overturning, injuring several people, and sending one individual to London Hospital.

In 1821, John Topp left his lodging at Nightingale's house in Westminster to attend Fairlop Fair. Upon returning, he found his room's door smashed, and items, including a locked tin box with a considerable amount of money, missing. William Garton and Robert Thurston were arrested, with Garton found guilty and sentenced to death, while Thurston was acquitted.

In 1822, a horse being cared for by a young boy became startled and galloped, dragging a carriage into a crowd and resulting in the deaths of two children. Two women were transported to a surgeon with broken bones.