The City of London Police Act was passed on 17 August 1839, and the City of London Police as it now became known, was given statutory approval and pre-empted an attempt to merge the City’s existing police into the Metropolitan Police.

Law enforcement in the City had existed for centuries and Sir Robert Peel chose not to reinvent the wheel when he formed his Metropolitan Police in 1829. Rather he cherry picked ideas from the existing City Police including how they should dress.

From the 17th century, policing in the City was the responsibility of two Marshals and their six Marshalmen. Their varied duties included keeping the peace at executions & other public occasions, and ensuring that the Watch, of elected Ward Constables and Watchmen, was kept at night.

In 1737, the Nightly Watch was reorganised, but no effective daytime police existed in the City until 1784, when the Court of Common Council agreed to finance a City Patrol as a temporary expedient. Although small, it was subsequently discontinued in 1793 by the Court as an unnecessary burden on the City’s finances. Budget cuts even then.

In the early 1800s the City of London was patrolled by two groups; a Day Patrol and a Night Patrol. Numbers were small about 50 or so. The Night Patrol was disbanded in February 1831 and its members transferred into an enlarged Day Patrol which, with a new uniform, then became known as the City Day Police. Policing in the City at night was left to the Nightly Watch. The following year, the Court of Aldermen authorised the expansion of the Day Police to 100 men, modelled on the ranks, pay and conditions of the recently established Metropolitan Police. It became fully operational on 2 April 1832. Hence the beginning of warrant numbers in that year.

In November 1838, an Act of Common Council finally merged the two City police forces into one, called the Day Police and Nightly Watch, which had a combined establishment of 501. This led in the following year to the City of London Police Act.

Initially the police stations were the old watch houses or other suitable premises and there were six of them; Moor Lane, Smithfield, Black Horse Court Fleet St, Garlick Hill, Seething Lane, Bishopsgate churchyard. with the Chief Office at 26 Old Jewry. The stations covered Districts, later called Divisions, and were numbered 1 – 6. Later new stations were built; Smithfield moved to Snow Hill, Black Horse Court to Bridewell Place, Seething Lane to Minories and Bishopsgate churchyard to further north in Bishopsgate.

An accommodation review in 1914 led to a reorganisation into four Divisions (identified as A-D), and both Bridewell Place & Minories Police Stations were closed.

The Second World War destroyed much of the area policed from the also destroyed Moor Lane and both the Division and station were merged with the remaining Snow Hill, Cloak Lane and Bishopsgate.

More recently, in 1965, Cloak Lane has been replaced by Wood St.