Derry City Council has voted to appoint an Army Veterans’ Advisory and Pensions Committee advocate to their group.
The move was confirmed by a meeting of councillors on Thursday despite opposition from Sinn Fein.
Within Northern Ireland the group has almost 4,000 ex-service personnel on disability pensions.
Sinn Fein Councillor Barney O’Hagan said the decision was unacceptable and the appointment was legally unsound.
“It is certainly inappropriate and highly insensitive for a body such as this to be invited in to Derry City Council seeking a person to advocate on behalf of the British armed forces.
“There are still a number of families in this city and throughout Ireland who are seeking justice for the actions committed against them by those British military forces,” he said.
But SDLP Councillor Gerard Diver accused Sinn Fein of shifting their position.
“We heard some reports which seemed to suggest that the issue was around the unacceptability of this particular veterans’ organisation because they were representing former members of the British armed forces.
“But the argument seemed to shift at the meeting toward the discomfort of the principal or the idea of the council appointing somebody to an organisation and how that might open the floodgates for lots of other organisations.”