Sectarian tensions fear over return of customs
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 police and government officials in the Republic last week expressed concerns over the inevitable introduction of new custom controls along the Irish border if Britain leaves the EU.
It is feared that any custom checks along the border will spark tensions between nationalist and unionist communities. Gardai also believe border checks could become targets for dissident republican terrorists.
A senior Irish government source said: "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 Republic's Revenue Commissioner is currently examining what additional resources would be needed for custom controls if Britain votes to leave.
Last week, former PSNI chief constable Hugh Orde accused NI 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.
Mr Orde is one of two former PSNI chiefs who have warned quitting the EU will make Britain less safe and urged voters not to "gamble with our security".
In an open letter, a group of former police bosses from across the UK has insisted leaving the bloc would put the country at a disadvantage in the fight against terrorism and organised crime.
The group, which includes former PSNI chief constables Sir Matt Baggott and Sir Hugh Orde as well as two former Metropolitan Police commissioners, said claims the UK is more vulnerable if it remains a member lack credibility, arguing that "all the evidence" shows the opposite.
"The EU helps our police forces to work together, making it harder for criminals and terrorists to evade justice," they wrote. "The arrest of Hussain Osman, who plotted a bomb attack in London and tried to flee to Italy, was thanks to European Arrest Warrant.
"We do not believe that staying in Europe makes us more vulnerable, it is not credible to argue so, all the evidence is to the contrary. We can see no case for taking such a gamble with our security that leaving the EU would entail."