Britain said yesterday that all the main paramilitary groups from the Northern Ireland Troubles, including the Provisional IRA, remain in existence but that the biggest security threat was posed by dissident republicans.

However an assessment by Northern Ireland’s police service and Britain's domestic intelligence agency, MI5, showed none of the paramilitary organisations from the Troubles was currently planning attacks.

“The assessment confirms that all the main paramilitary groups operating during the Troubles are still in existence,” Northern Ireland Minister Theresa Villiers told parliament. “Dissident republicans remain a severe threat and at any given time a terrorist attack from them is highly likely.

“The Provisional IRA remains in existence though in a much reduced form,” Ms Villiers said.

She said that some Provisional IRA members were involved in criminality but that the leadership remained committed to the peace process.

Northern Ireland was last month taken to the brink of its worst crisis since a 1998 peace deal after a murder linked to former members of the IRA prompted first minister Peter Robinson, to step aside.