The British government's new counter-terrorism strategy claims that Northern Ireland-rooted terrorism poses a greater threat to Great Britain.
According to the strategy, which has been updated for the first time since 2009, the number of terrorism-related arrests in Northern Ireland was 98 percent higher in 2010 than in 2009.
"We face an ongoing and serious threat from Northern Ireland-related terrorism", claimed Home Secretary Theresa May.
While the level of the terrorist threat within Northern Ireland is rated as severe, in Great Britain the threat level is considered substantial, meaning there is a "strong possibility" of an attack.
Terrorist attacks increased from 22 in 2009 to 40 last year and 16 so far this year, including the death of Constable Ronan Kerr in Omagh in April. Many more have been successfully disrupted, according to the strategy.
"The UK has a long experience of Northern Ireland-related terrorism”, said the 125-page document.
"Following the Good Friday agreement in 1998, many Northern Ireland terrorist groups agreed a ceasefire and subsequently decommissioned their weapons.
"Despite this significant and continuing progress in stabilising the political situation in Northern Ireland, some republican terrorist groups continue to carry out terrorist attacks", the document added.
Support for Northern Ireland-related terrorism remained "low", the document said, and dissident groups did not represent mainstream opinion - but the frequency of attacks has "increased significantly".
Between January 2009 and December 2010, there were 316 terrorism-related arrests in Northern Ireland, of which 97 were charged and nine were convicted.
The new strategy, which also looked at the potential threats to the London Olympics in July next year, came after the threat level from international terrorism was reduced from "severe" to "substantial".
"We know we face a real and serious threat from terrorism and I have always been clear that protecting national security and the safety of the British people is the first priority of this government”, said the Home Secretary.
"The new counter-terrorism strategy is our response to the continuing and evolving threat that we face as a country", she added.