Crime and punishment has naturally played a part in the existence of every town or village like Llantrisant.

One of the early records shows that in April 1808 a Llanharry youth, of nineteen, named Williams Williams was executed at Cardiff gaol for the murder of a Llantrisant boy named David Williams who was just twelve years of age.

According to the Cambrian News of the period, the "prisoner and the deceased were in habits of intimacy and that the latter had mentioned to one of his playmates that the prisoner had been guilty of a crime...and the prisoner threatened to kill the boy and throw him in the river."

The young David Williams was found one Sunday afternoon in a ditch with seven stab wounds to the neck and stomach.

William Williams was caught at Gelligaer, where he worked and he appeared in the Glamorganshire Assizes in Cardiff where he was found guilty.

The news report concluded: "He was executed on Monday last on the new drop at Cardiff, amidst a great concourse of people who assembled on the occasion."

The large iron town of Merthyr Tydfil was the first in the south Wales to appoint a metropolitan policemen and although there was a desire for protection but a general reluctant to pay for it. 

Their metropolitan officer, Jamieson took appointment. By 1836 Bridgend, another growing town, employed a policemen  The government of the county was in the hands of the magistrates of the county assembled in quarter sessions and it was in this body in April 8th 1839 that considered the provisions of the County Police Act of that year which empowered them to provide paid police force in the county. 

It was in April 1839 that the Quarter sessions in Cowbridge appointed a constable for Miskin. Until then parish constables had been elected annually at petty sessions. There were three constables appointed by October and a few months later a superintendent of police for Miskin was advertised to cover Llantrisant, Pentyrch, Llantwit Fardre and Llanwynno.

Freeman of Llantrisant Major Rickards proposed the establishment of a police force because of the danger of insurrection such as the Chartists and the Marquis of Bute supported his proposal. Pc James Hume came to Llantrisant in April 1840 with superintendent.

Thomas Morgan Lewis appointed and took up residence on the Bull Ring. The other constables were appointed in Treforest, Pontypridd, Nantgarw, Caerpillhy, Nelson. Their uniform was a blue dress coat with scarlet cuffs and a scarlett embroidered collar, dress trousers, blue and white cast cape. Also a box leather hat, stock and clasp, staff, battle lanthorn and handcuffs. By 1841 it was agreed that they should carry a cutlass at night.