The Northern Ireland Secretary, Peter Hain, has announced that the government no longer recognises the Ulster Volunteer Force (UVF) as being on ceasefire. But what exactly is the UVF?
The Ulster Volunteer Force was formed in 1966 to combat what it saw as a rise in Irish nationalism centred on the 50th anniversary of the 1916 Easter Rising.
It adopted the name and symbols of the original UVF, the movement founded in 1912 by Sir Edward Carson to fight against Home Rule. Many UVF men joined the 36th Ulster Division of the British Army and died in large numbers during the Battle of the Somme in July 1916.
UVF murals can be found on many streets in N Ireland
Fifty years later, the Prime Minister of Northern Ireland, Captain Terence O'Neill, would rush back from a commemorative service at the Somme to ban the UVF.
It had been formed a few months earlier with the express intention of executing "mercilessly and without hesitation" known IRA men.
Their first three victims, a Protestant woman and two Catholic men, had no connections with the IRA.
It was the murder of barman Peter Ward, the third victim, which brought the UVF and its leader Gusty Spence to public attention. Spence was convicted of Ward's murder and sentenced to 20 years in prison.
The new UVF opposed the liberal reforms being introduced by PM O'Neill. In March and April 1969 they bombed water and electricity installations as part of a broader political campaign to force O'Neill to resign.
The bombings were blamed on the IRA. O'Neill resigned at the end of April.
According to the book Lost Lives, between 1966 and 1999 the UVF and an affiliate group, the Red Hand Commando, killed 547 people.
Many were killed in high profile attacks. In December 1971 they planted a bomb at McGurk's bar in Belfast killing 15. By the mid-70s a vicious UVF unit known as the Shankill Butchers was engaged in horrific sectarian killings.
The LVF broke away from the UVF in the mid-1990s
In May 1974 the UVF was suspected of planting bombs in Dublin and Monaghan killing 33 people and in 1975 they shot dead three members of the Miami Show Band.
In October 1975 the UVF was undermined when soldiers and police swooped on houses in Belfast and East Antrim and arrested 26 men. The following March they were sentenced to a total of 700 years in prison. The police got more evidence in 1983 when a UVF commander turned informer.
In October 1994, the Combined Loyalist Military Command, which included the UVF, called a ceasefire. Gusty Spence made the announcement, expressing "abject and true remorse" to all innocent victims of loyalist violence.
David Ervine leads the UVF's political wing, the PUP
The UVF's political wing, the Progressive Unionist Party, played a prominent role in the peace process and supported the 1998 Belfast Agreement.
Since 1996, the UVF has been embroiled in a feud with the Loyalist Volunteer Force. In August 2000 a murderous feud broke out between the UVF and the UDA's C Company, led by Johnny Adair, on Belfast's lower Shankill Road.
By the time a truce was negotiated in December 2000, seven men had died as a result of the feud and hundreds of families were displaced.
In recent months the simmering feud between the UVF and the LVF has boiled over again with several murders in and around Belfast.