The Order of St John is operating internationally in over 30 countries worldwide with a coordinating office in London, United Kingdom. Its origin in Jerusalem when a hospice - place of care was established by the Nuns and Monks to provide care to the pilgrims to the holy city of Jerusalem in 1070. St. John Ambulance was established in United Kingdom in 1887 during the industrial revolution to provide First aid and ambulance services to the injured persons at work.
The same mission was replicated in Uganda in 1930 with direct administration from the British governors until 1962 when Uganda gained independence. It has since operated as an International NGO providing First Aid and ambulance services among others, operating through over 10,000 volunteers organised in divisions and spread all over the country.
Source * https://www.stjohnuganda.org/about-us