Chief Constable Simon Byrne said: “The picture in relation to last week’s data breach continues to evolve at pace.

“We are now confident that the workforce data set is in the hands of Dissident Republicans.

“It is now a planning assumption that they will use this list to generate fear and uncertainty as well as intimidating or targeting officers and staff.

“I won’t go into detail for operational reasons but we are working round the clock to assess the risk and take measures to mitigate it.

“Contrary to commentary circulating we are not seeing any movement of officers or staff out of the organisation. I’d like to pay tribute to our people who have demonstrated tremendous resilience since news of this breach broke last week.

“Weekend events have shown their determination to stick to our values and continue to serve the public with commitment and professionalism.

“We are being strongly supported by a range of specialists from across the policing system in dealing with this unprecedented incident.

“We have measures in place to reassure and advise our workforce of what this risk means for them. 

“We will continue to liaise with the Policing Board, the UK Government and partners as we develop our response to this.

“The safety and welfare of our officers and staff remains my top priority.”