Terrorist groups - home based:
Continuity Irish Republican Army (CIRA): aim(s): disrupt the Northern Ireland peace process, remove British rule in Northern Ireland and, ultimately, unify Ireland area(s) of operation: based and operationally active primarily in Belfast and along the border areas of Northern Ireland, where operatives have carried out bombings, assassinations, kidnappings, hijackings, extortion, and robberies over the years; articulates its intent to target drug dealers and other criminals, especially those who harm any Republican, including RIRA members; remains sporadically operational targeting primarily the British military, Northern Ireland security forces, and Loyalist paramilitary groups; attacks in recent years involve shootings and small-scale bombings; does not have an established presence on the UK mainland; accused in 1996 of directing operatives to park a vehicle with 1,500 pounds of homemade explosives at the Killyhelvin Hotel in Enniskillen, County Fermanagh, Northern Ireland; on 15 July 1996, at least 11 people were injured and most of the immensely popular and newly refurbished hotel was demolished; the attack occurred during the original IRA's first ceasefire; estimated in 2016 to have 50-100 members
Real Irish Republican Army (RIRA): aim(s): committed to using violence to remove British rule in Northern Ireland, disupt the Northern Ireland peace process, and unify Ireland area(s) of operation: based and operationally active in Northern Ireland, where operatives continue to conduct occasional shootings and small-scale bombings; RIRA claimed responsibility for the 2 April 2011 murder of the Police Services of Northern Ireland's Constable Ronan Kerr, who was killed when a booby-trap bomb exploded under his car in Omagh; RIRA conducted its deadliest attack in the UK on 15 August 1998, when operatives detonated a vehicle-borne improvised explosive device with 500 pounds of explosives on a busy street in Omagh, killing 29 people and injuring at least 220; maintains a limited presence in Great Britain; estimated in 2015 to have a 100 active members

Terrorist groups - foreign based:
Islamic State of Iraq and the Levant (ISIL): aim(s): bolster its support and recruitment networks in the UK and, ultimately, destabilize the UK economy area(s) of operation: maintains support and recruitment networks; Anjem CHOUDARY and associate Mizanur RAHMAN pled guilty on 16 August 2016 to inviting support for ISIL; CHOUDARY founded the banned UK-based extremist movement known as al-Muhajiroun, which UK authorities accuse of recruiting and facilitating activities on ISIL's behalf; the UK is a top source country in Europe for ISIL recruits; as of early 2017, approximately 750 to 850 British citizens were fighting in Syria or Iraq alongside ISIL, planning to go to fight, or had returned from the fight