Over 10,000 Auxiliaries and Black and Tans served in Ireland between 1920 and 1922. They were recruited from the ranks of British ex-servicemen, with Tans having largely served in the non-commissioned ranks, whereas the Auxiliaries tended to have been in the officer corps, although a good many had achieved promotion from the ranks indicating that the Auxiliary Division was not as socially elite as previously believed.
On average the Auxiliaries were older (29 years) than the Tans (26 years). Many had distinguished First World War records, with 13 per cent of the Auxiliaries decorated for gallantry.
Historian D.M. Lerson has effectively contradicted the traditionally derogatory view of these men as 'ex-convicts and psychopaths, hardened by prison and crazed by war.' In fact very few had criminal records and prior to the First World War had served in a wide range of occupations.
An analysis of one cohort of 19 Auxiliaries who were ambushed by the IRA at Clonfin in County Longford in February 1921, resulting in the deaths of four of them, reveals that their average age was 26; 95 per cent were Protestants (14 Anglicans, 3 Presbyterians and 1 Baptist), the only non-Protestant being a Scottish Catholic. Only three had pre-war armed forces service (one in the army and two in the navy).
Other occupations included an actor, a teacher, engineers and mechanics, shop assistants, messengers and clerks.
While the overwhelming majority of both forces were English, the Clonfin cohort included two Scots, a Welshman and a South African. The latter is believed to have participated in the Boer War on the South African side, while one of his Auxiliary comrades was a British Army veteran of the same conflict.
One of the Clonfin Auxiliaries was a Presbyterian from Queen's County (Laois). The number of Irish recruits is not known definitively though among the better known Irish Auxiliaries was Gerard Tynan-O'Mahony, a member of a distinguished Irish legal and literary family.
The previous military and combat experience of both forces raises questions about their preparedness for adapting to the guerrilla warfare conditions which they faced in Ireland. Historian A.D. Harvey identified the Royal Air Force as the organisation to which 'the largest single group of officers had belonged', while historian Andrew Nelson has shown that the combat experience of more than half of the Auxiliary Company ambushed at Kilmichael in County Cork in November 1920 was exclusively in trench warfare.
This lack of adequate experience was compounded by inadequate training, with fatal consequences in some cases. The majority of the Auxiliaries involved in the ambushes at Clonfin and Kilmichael had less than two months service in Ireland.
Motivations for joining included the difficulty readjusting to civilian life after the Great War, the opportunity to experience the camaraderie of being part of an armed force again, and the economic benefits of a well-remunerated job at a time when unemployment among ex-servicemen in Britain was high.
William Bellingham, who was wounded at Clonfin, stated that 'he joined the Auxiliaries merely to tide him over in the crisis in the engineering trade'.
In spite of their Irish experience the desire to continue in uniform clearly remained with some; disbanded Auxiliaries and Tans served in the British Palestine Gendarmerie and in other colonial police forces where some ex-RIC were re-settled after the force was disbanded in 1922, others returned to civilian occupations in Britain and elsewhere, while some of the younger men saw military service again during the Second World War.