Brexit could spark violence in the North
There are heightened fears across the justice system that the reintroduction of border controls after a Brexit vote will reignite sectarian tensions in Northern Ireland.
Senior gardai and officials in the departments of Justice and Foreign Affairs last week expressed concerns over the inevitable introduction of new custom controls along the Border between the Republic of Ireland and Northern Ireland if Britain leaves the EU.
It is feared that any custom checks along the Border will spark tensions between nationalist and unionist communities in the North. Gardai also believe border checks could become targets for dissident republican terrorists.
A senior government source told the Sunday Independent: "There are concerns in the diplomatic and security regimes on both sides of the Border that a reintroduction of the Border would lead to new concerns in relation to issues that have been improved in recent years."
The Revenue Commissioner is currently examining what additional resources would be needed for custom controls if Britain votes to leave.
Last week, former chief constable of the Police Service of Northern Ireland Hugh Orde accused Northern Ireland Secretary Theresa Villiers of having her "head firmly stuck in a peat bog" over her claim that borders may not be reintroduced if Britain leaves the EU.
Meanwhile, Provo smugglers in the border area have broken from Sinn Fein and are supporting British withdrawal from the European Union, according to garda and local sources.
The smugglers held a meeting last weekend under cover of a 'conference' and decided heavily in favour of Brexit.
According to sources, the meeting was attended by all the main smugglers in the border area, including close associates of jailed South Armagh IRA boss Thomas 'Slab' Murphy.
Garda sources say they do not see the pro-Brexit stance as signalling any kind of a desire to return to the IRA campaign to bomb Northern Ireland out of the UK.
Instead they see likely difficulties for both UK and Irish customs in their attempts to prevent a major resurgence of smuggling in the event of Brexit.
Gardai do not believe the smugglers' intentions are to resume 'hostilities' against the British state as this would draw soldiers and extra police into the border area after years of 'light-touch' security which allowed the smugglers to make fortunes in the aftermath of the IRA 1997 ceasefire.
However, gardai believe that any attempt to impose permanent border checkpoints could lead to these becoming targets for attack.
Customs posts were traditional targets for the IRA along the Border mainly to allow it to conduct major smuggling operations.
Last December, Sinn Fein announced it was campaigning against the United Kingdom's withdrawal from the European Union, saying it believed Brexit could be "disastrous for Ireland".