Des O'Hagan, who has died aged 81, was a link to the Northern upheavals in the early 1970s. He was director of education of Official Sinn Féin and then the Workers Party and gave a political formation to a significant generation in politics, the trade unions and the media. His intellectual analysis was central to the Workers Party's move away from nationalism.
In 1971-2 he was interned. The 21 "Letters from Long Kesh" he smuggled out were published in The Irish Times. O'Hagan was also a link to the republicanism of the 1950s, having been imprisoned as a member of Saor Uladh, a Northern split from the IRA.
Desmond Patrick O’Hagan was born in Belfast’s Lower Falls, youngest of three children and second son to Peter O’Hagan, a watchmaker, and his wife Susan (née McKeown). He was educated at St Malachy’s College in Belfast and while at school joined the IRA.
After school he joined the civil service, working in a planning office. At the time, Northern civil servants had to swear allegiance to the monarch. For this, O’Hagan was expelled from the IRA. He joined Saor Uladh, finding its heterodox atmosphere more comfortable.
Jailed after an unsuccessful attempt to rescue a Saor Uladh prisoner from hospital, he worked on pioneering academic education among republican prisoners. The orthodox IRA initially disapproved, but ultimately joined in.
On release he moved to study at the London School of Economics, where he was influenced by Marxist lecturers, including Ralph Miliband, father of Ed and David.
Returning to Belfast, he became a lecturer at Stranmillis teacher training college. There he gave students his philosophical opinions, but allowed them to develop their own. He also re-engaged politically, becoming a founder member of the Northern Ireland Civil Rights Association.
Internment ended his academic career. Stranmillis was an overwhelmingly Protestant institution. Some colleagues and students backed him. He resigned because he didn’t want to split the college. He also felt the lure of full-time political activism.
O'Hagan was always a fierce polemicist, strongly opposed to the (Provisional) IRA. His Marxism was broadly pro-Soviet. For some he was inspirational, for others a bête noire. He survived at least two attempts on his life during republican feuds. He was also interested in culture, developing the "Poets and Pints" initiative, where poets read their work in clubs and pubs in working class areas of Belfast.
In later life he moved to Downpatrick. He stood for the Workers Party in various elections and kept faith with its vision despite low votes.
He is survived by his sons Donal and Aedan, his sister Angela, brother Raymond and former wife Liz (McShane). He was predeceased by his wife Marie and son Ciaran.