The incident – which involved a mechanic – occurred last week when the man was seeking entry to Newry fire station.

A senior fire service employee, who wished to remain anonymous, has told of his concern at what he claimed was the development of an anti-British mentality.

Last year, survivors and relatives of the 1987 Enniskillen Poppy Day bomb reacted with fury when a picture in the town's fire station, depicting a montage of the 12 victims, was removed over fears it breached equality guidelines.

Upon arriving at Newry station, the mechanic was told by a member of staff that he was in breach of the Flags and Emblems Act because he was wearing a poppy, and he would have to remove it or he would not get in.

The senior firefighter who was informed of the incident said there was a "lot of anger" in the service in reaction to the poppy snub.

"Staff members are appalled at the incident," he said. "It is just another example of the attempts to 'de-British' workplaces and public places, the same as happened at Enniskillen.

"Where does it end? Do they want to ban the poppy from the fire service, from PSNI stations, from other public services?"

He said: "My understanding is that what this man was asked to do, in removing his poppy, was not legal. There is a policy in the fire service for uniformed officers, which states you can wear a poppy on the seven days before Remembrance Day. But that policy does not apply to civilian staff, who can wear their poppy as they wish."

DUP MP Jeffrey Donaldson said the Newry episode was "entirely unacceptable".

"It is not an offence nor is it contrary to fair employment regulations for an individual to wear a poppy in a place of work," he said.

"The senior command of the fire service need to take action to protect the rights of all its staff who wish to wear their poppy in this way."

Ulster Unionist deputy leader Danny Kennedy, who represents the Newry area, viewed the development with "serious concern".

"It is everyone's right to purchase and wear a poppy and this is an interference of the individual's right to remember the dead of two world wars," he said.

A spokesperson for the fire service confirmed a full investigation into the matter will now be conducted.

"Northern Ireland Fire and Rescue Service has been made aware of an issue relating to a member of staff who was wearing a poppy on a routine visit to a fire station.

"NIFRS has a policy on approved badges and emblems, which includes when poppies can be worn," she said.