LONDON (Reuters) - The chances of an attack on Britain from Northern Ireland-based republican militants has fallen, the government said on Wednesday, following steady progress towards peace after decades of conflict.
Dissident republican activists have scaled back attacks on England in the years since a 1998 peace deal, which largely brought to an end three decades of sectarian violence that killed 3,600 people in British-controlled Northern Ireland.
The threat level from Northern Irish militants has been lowered to moderate, the second lowest of five levels, from substantial. "This means that a terrorist attack is possible, but not likely," interior minister Theresa May said.
International monitors say the Irish Republican Army has all but given up its weapons and its political wing Sinn Fein has joined a power-sharing government. But splinter groups have continued sporadic attacks in Northern Ireland.
Across the 1970s and 1990s, dissidents bombed civilian, military and political targets in England - including a failed attempt to kill former prime minister Margaret Thatcher - as part of a campaign for independence from London's rule.
The last spate of violence by Irish republicans in England took place in the years immediately following the peace talks, when the Real IRA group - who opposed the deal - claimed responsibility for several attacks in 2000 and 2001.
By contrast, militants have remained active in Northern Ireland, targeting soldiers and police in recent years. London believes the chances of an attack in Northern Ireland by groups based there remains "highly likely".
Britain's focus on combating attacks on home soil has shifted over the last decade to dealing with threats from Islamist militants. Fears of an attack during the London Olympics this year proved unfounded.
In 2005, suicide bombings on London's transport system killed 52 people and British police continue to arrest individuals suspected of plotting attacks.
"Despite the change which has been made today, there remains a real and serious threat against the United Kingdom from terrorism," May said. The threat level from international militants remains at substantial.
(Reporting by Matt Falloon; editing by Robert Woodward)