O'Connell was born in Kilkee, in rural County Clare, 'a stronghold of Gaelic-speaking inhabitants and old-guard IRA sympathisers', to a farming family.
O'Connell lived for a time in Lower Market Street in Ennis, sharing a flat with a future member of the same Active Service Unit (ASU), Harry Duggan.
Irish republicanism, as well as being entrenched in the area, was also not unknown of in his family - his brother Michael had already served a prison sentence for IRA membership and possession of explosives.
[2] O'Connell and fellow ASU member Brendan Dowd flew from Shannon Airport, County Clare to Heathrow in early August 1974, under the guise of looking for work in London.
[5] They were presented by Gerry Adams to the 1998 Sinn Féin Ard Fheis as 'our Nelson Mandelas', and were released together with Brendan Dowd and Liam Quinn in 1999 as part of the Belfast Agreement.