SINN Féin's leader on Belfast City Council is stepping down.
Jim McVeigh, who was initially co-opted onto the council in 2010 to replace West Belfast MLA Pat Sheehan, plans to concentrate on his trade union work.
The 55-year-old former prisoner and last IRA officer commanding in the Maze prison, is an industrial organiser with Siptu.
He will officially resign as a councillor next month but will remain a party activist.
Sinn Féin said his replacement as a councillor and as party group leader has yet to be decided.
Mr McVeigh said it was privilege to have represented the citizens of Belfast for seven years and to have led the Sinn Féin team on Belfast City Council, the local authority's largest grouping.
"Our team there have championed and promoted equality and respect for all citizens and all communities across Belfast," he said.
"We led the drive for an investment strategy which has delivered unprecedented resources for public services and public amenities, creating and sustaining thousands of jobs across Belfast."
Unionists regard believe his appointment as Sinn Féin group leader coincided with a hardening of the party's attitude. Mr McVeigh was regarded by many unionists as the driving force behind the council's 2012 decision to fly the Union flag on designated days only.
The part-time author, who latest book 'Goodbye Dearest Heart – the Story of Lieutenant General Joseph McKelvey' was published last year, said he would now be concentrating on helping advance workers’ rights across Ireland.
"I will remain a Sinn Féin party activist and will be working with our party chairperson Declan Kearney to develop and strengthen our party's policies on workers’ rights, particularly in the north," he said.
"I am also looking forward to helping deepen Sinn Féin's overall relationship with the Irish trade union movement and working to promote Irish unity."
Mr McVeigh is the second Belfast Sinn Féin councillor in recent days to announce his resignation.
Gerry McCabe, who represented the Oldpark area in north Belfast, stepped down last week to take up a full-time job.
