Not surprisingly, it was a Germanic tribe, the Saxons, that introduced the Policing System to England in the 5th century.
The Saxon rulers divided their people into groups of ten, named "tythings." One of the ten was representing the group; each ten tythings had its "hundred-man" who was responsible to the Shire-reeve, or Sheriff, of the County.
This system took deep root by the 17th and 18th centuries, when each parish appointed or elected annually a suitable person to serve for a year as the parish constable.
Already then the job was underpaid, and in fact the first constables were not paid at all.
In the towns, it was the guilds’ responsibility to keep the public peace, and they hired men to guard the city-gates and enforce the nightly curfew. Their name, "The Watch” derives from the mission of keeping the streets empty as a measure to prevent crimes from being committed -- in the streets.