A fresh terrorist attack in Northern Ireland is highly likely according to the latest intelligence assessment of the capabilities of dissident republican groups.
The threat level in the North is viewed by British intelligence agency MI5 as severe, although the danger posed by Irish dissidents in Britain has dropped from substantial to moderate.
The highest threat level is critical; "severe" means an attack is highly likely, while "substantial" is interpreted as an attack being a strong possibility; "moderate" means it is possible but unlikely.
Within the past few years the renegade republicans have killed three PSNI constables and two British soldiers and carried out several other attacks on the security forces in the North.
Anti-terrorist officers are also concerned at the dangers posed by a new alliance formed in the summer and comprising a Real IRA faction based in Derry, the vigilante-style Republican Action Against Drugs, which already had links with the Real IRA; a group of non-aligned dissidents, mainly former Provisionals from Tyrone; and the Real IRA faction formerly led by Alan Ryan, who was murdered by a crime gang near his home in north Dublin last month.
This alliance, combined with the Continuity IRA and an outfit known as ONH, has around 600 activists.
Dissident republicans have been responsible for 19 terror attacks in Northern Ireland so far this year.
The threat level there has been at severe since March 2009 following the murders of two British soldiers and a police constable in attacks by the Real IRA and Continuity IRA.
It had previously been at that level in August 1998 when 29 people were killed in the Omagh bomb atrocity.