[1] He moved back to Belfast in 1971,[2] where he became a full-time official for NIPSA,[1] while organising a Trotskyist group within the Northern Ireland Labour Party (NILP).

Hadden and his supporters were expelled from the NILP in 1977 [3] and they instead founded the Labour and Trade Union Group to contest elections as an independent organisation.

Hadden stood for the Labour and Trade Union Group in Belfast South at the 1992 general election, taking 2.2% of the votes cast.

[4] At the 1993 Northern Ireland local elections, he stood in the Lagan Bank division of Belfast City Council as a Militant Labour candidate, but took only 142 votes.

[7][8] Militant Labour became the Socialist Party, and Hadden remained its leading figure in Northern Ireland until his death in 2010.