The following year saw the establishment of the St John Ambulance Brigade (a spin-off of the Association), comprising a body of uniformed volunteers ready to render first aid to the sick and injured.

Miss Eileen Blandford joined the Brigade in 1913 and in 1914 became District Secretary, working closely with Dr John Lumsden.

The Brigade was involved with many major events in Irish history, including treating casualties from the clashes during the 1913 Dublin Lockout.

However, the Brigade became prominent in Dublin during the Easter Rising of 1916 where it treated casualties on both sides and fed and cared for evacuees.

She helped to set up an emergency hospital at the Brigade's headquarters at 14 Merrion Square during the Rising and "cycled daily through the firing line to visit the hospital"[6] For these acts, and his role in establishing the St John Ambulance Brigade in Ireland, Lumsden was knighted as KBE by George V.[5] At the same time Dr Ella Webb was appointed an MBE for her work.

The service later became the National Blood Transfusion Association in 1948 but owes its origin to the Brigade and more especially to Sir John Lumsden.

In 2019, an investigation by the Child and Family Agency (Tusla) concluded that allegations of abuse made against a former senior member were founded.

[10] The board of St. John Ambulance commissioned Judge Geoffrey Shannon to undertake a full internal review and his subsequent report led to significant changes in the organisation to ensure best practice in child protection.

Members will be appointed, for a defined term of office, to roles based on their skills and experience, rather than the time served.

These are black for ordinary members & cadets, red for doctors, grey for nurses, and green for PHECC registered practitioners.

As with St John Ambulance in England since the 19th century, this style has been essentially copied from successive versions of a (London) Metropolitan Police No.1 (ceremonial/formal) uniform.

High visibility jerkins & jackets in fluorescent yellow with green yokes are worn by all ranks when required on operations.

Rank slides are worn on the shoulders of all shirts, jackets and high visibility wear – whichever is the outer layer.