by BBC NI chief security correspondent Brian Rowan

The murder of the prominent Portadown loyalist Richard Jameson is being linked by security sources to a long-running feud between rival paramilitary organisations.

Jameson, a local commander of the outlawed loyalist paramilitary Ulster Volunteer Force, was shot from close range as he arrived home on Monday night.

He was hit five or six times in the head and chest and died soon afterwards.

The murder is being linked to the splinter group, the Loyalist Volunteer Force, which is supposed to be on ceasefire. If early security assessments of the murder are firmed up this will be the third killing the LVF has been linked to in the past year.

The group is also suspected of murdering the Lurgan solicitor Rosemary Nelson and the grandmother Elizabeth O'Neill.

The latest shooting will also prompt another review of the LVF ceasefire and could have implications for the early release of their prisoners.

Thirteen are currently being held on the wings of the top security Maze jail including five remand inmates.

Internal row

The long-running feud between the UVF and the LVF dates back to 1996.

That year the UVF leadership stood down Billy Wright and his terrorist unit based in Portadown and, out of this internal row, the LVF emerged.

The UVF move came after the unsanctioned killing of Catholic taxi driver Michael McGoldrick which breached the ceasefire announced by the Combined Loyalist Military Command in 1994.

Wright was later murdered by members of the INLA inside the Maze jail and in the period after the shooting the LVF was seen at its most active as it engaged in gun attacks in several parts of the province.

A number of Catholics were killed and police investigations showed that at least one of the gun attacks was carried out by the larger loyalist group the Ulster Freedom Fighters, who used the title of the LVF to try to cover up their involvment.

UVF recruitment drive

Since Wright's murder the UVF has been recruiting around Portadown and has moved to re-establish itself as the dominant paramilitary force in the area.

There has been evidence of continuing tensions between it and the LVF including a clash in a club over the Christmas holiday period when a number of people were seriously injured.

But the murder of Richard Jameson marks a very serious escalation in the feud.

Members of the UVF will want to hit back and the unanswered questions at this time are - will the leadership of the UVF be able to hold their members back? Will they want to after this murder and what influence will the loyalist political representatives, David Ervine and Billy Hutchinson, have at this time?

Ervine has not confirmed that Richard Jameson was a senior figure in the UVF but in his condemnation of the shooting he has come close to blaming the LVF.

The Progressive Unionist Assembly member spoke of drug dealers who "masquerade as loyalists". The LVF is suspected of involvement in the illegal drugs trade.

No-one knows how things will develop from here but no-one is playing down the seriousness of the situation.