Police are probing a sinister threat made to employees working at Northern Ireland’s Border Control Ports.
The investigation was launched after graffiti warning that “all border post staff are targets” appeared in Larne.
It prompted officials at the Department of Agriculture, Environment and Rural Affairs (DAERA) to alert the operators of the facilities at Larne, Belfast and Warrenpoint.
A leaked internal memo seen by the Belfast Telegraph was sent out by the Brexit Operational Readiness department.
It said: “To be aware, the below appeared overnight near Larne Port. There is nothing to suggest at this time that this is anything other than an isolated incident.
“However, this may understandably cause you/your teams concern but be assured that DAERA have engaged with the PSNI, who are dealing with the matter appropriately.
“DAERA will continue to liaise with the PSNI to ensure that your health, safety and welfare, and that of our delivery partners, remains our utmost priority.
“I would be grateful if you could ask your relevant staff to report anything suspicious in the area of the Port to either ourselves, PSNI or Port Security.”
Border Control Post (BCP) facilities came into operation from January 1 because of Brexit with a de facto Irish Sea border regarding movements of goods from Great Britain and the Northern Ireland protocol.
While its fundamental purpose is to prevent a hardening of the border between Northern Ireland and the Republic of Ireland it means that instead there are customs checks at our ports.
TUV leader Jim Allister said: “No one, either through actual threats or headline-grabbing threats, should be resorting to matters pertaining to violence in respect of any issue.
“There is a place for, indeed a necessary place, for political opposition to the partition of the United Kingdom. But that should be coming from particularly the political leadership of unionism.”
Alliance East Antrim MLA Stewart Dickson added: “While there is no excuse for this, sadly some will attempt to justify it by linking it with Brexit. The reality is, it is just thugs again attempting to assert their dominance in the area.”
DUP MP for East Antrim Sammy Wilson said: "Throughout all of this Brexit debate, the only people who have threatened violence as far any checks are concerned, have been those who supported the Remain campaign.
"And that includes people who time and time again talked about threats of violence from the IRA and republicans if there were border posts put along the border between Northern Ireland the Irish Republic and yet they have been strangely silent, the same crowd, when a border has been placed between Northern Ireland and GB.
"So unionists are the only people who never at any stage threatened there would be violence as a result of whatever arrangements came and arose from Brexit.
"And that is still my position and still our position that this is still an issue that unionists feel very sore about, feel betrayed by, have fears about the future because of the erection of these border posts and the disruption which they have caused and the difference which it makes between us and the rest of the United Kingdom.
"But I believe, and indeed there has been evidence already this week, that through political pressure and through using what leverage we have we can first of all get some of the immediate problems of the protocol dealt with and in the longer run I believe the protocol itself will be shown to be unworkable.
“There is a political battle to be fought here and I don’t think anything will be achieved by writing messages on the walls and it has not been the approach which unionists have.”
Meanwhile, a source has said there are fears in Warrenpoint that the BCP there could be targeted by dissident republicans.
They said: “Where it’s located is at the Narrow Water Castle, and anyone who knows the history about Narrow Water will know about the bomb that went off there (in 1979, killing 18 soldiers). So there is a credible threat as nobody wants to see a border infrastructure of any shape or description in this area, and similarly I don’t think the loyalists want to see border inspection in Larne.”
A DAERA spokesperson said the department was “aware of this incident and are liaising with the PSNI”.
The PSNI said: “Police are aware of a graffiti incident the vicinity of Larne Harbour on January 21. This matter is currently under investigation.”