The unit was formed in 1921 at the former premises of the
Royal College Colombo in St Sebastian Hill,
Colombo. At its formation, the unit was limited to British personnel and consisted of eight mounted sergeants and constables, who were later promoted to sub-inspector grade. Gazetted Officers were also trained in equestrian. During
Royal visits mounted policemen joined in with the
Ceylon Mounted Rifles in providing mounted escorts starting in 1925. With the disbandment of the Ceylon Mounted Rifles in 1931, the mounted police took on the role of providing mounted escorts as the
Governor's Bodyguard on ceremonial occasions including independence celebrations in 1948. Following independence three Ceylonese was admitted to the unit for the first time. On the morning of March 22, 1952, Prime Minister
D. S. Senanayake was riding the police mare 'Chitra'. He suffered a stroke and fell (dying several hours later) at the
Galle Face Green. He was accompanied by Inspector
Eddie Grey, who would later become the first Ceylonese head of the mounted police. In 1956, the police mounted division was formed with a Sub-Inspector, two Police Sergeants and 22 Police Constables with 23 thoroughbred horses imported from Australia. ==Units==