Northern Ireland's police chief said he gets briefings virtually every day about plots to attack and kill his officers.PSNI Chief Constable Simon Byrne said the ongoing threat from dissident republicans remains a "real worry".And he said the shooting of senior detective John Caldwell sent a "shockwave" through the PSNI.Last year the threat level in Northern Ireland was raised from substantial to severe, meaning an attack is highly likely.There have been a number of terrorist incidents targeting

Northern Ireland's police chief said he gets briefings virtually every day about plots to attack and kill his officers.PSNI Chief Constable Simon Byrne said the ongoing threat from dissident republicans remains a "real worry".And he said the shooting of senior detective John Caldwell sent a "shockwave" through the PSNI.Last year the threat level in Northern Ireland was raised from substantial to severe, meaning an attack is highly likely.There have been a number of terrorist incidents targeting police officers since then, with the most serious being the gun attack on Detective Chief Inspector John Caldwell in February.Mr Caldwell, who has led many of the PSNI's most high-profile investigations, was shot several times outside a sports complex in Omagh, Co Tyrone, when he was with his son after coaching a youth football match.