Belfast's Shankill Road is no stranger to republican violence. In 1993, a Provisional IRA bomb killed nine Protestants in a fish shop. There have been countless gun attacks on loyalist paramilitaries on the road. But the current UDA/UVF feud has brought a sense of fear and foreboding to the area missing during even the darkest days of the Troubles.
Rival groups of armed paramilitaries were driving around its estates last night. The road was like a graveyard, its residents choosing to remain indoors. "Even the Provos never brought us to this," said one elderly resident.
Up to 100 British troops have been deployed in the district and the RUC presence has been stepped up. There have been two murders, around a dozen shootings, and attacks on two political offices and 12 homes within the space of 48 hours.
Observers fear it will get worse. The seriousness of the situation was illustrated by Mr Peter Mandelson, returning from holiday yesterday and holding a press conference at Belfast International Airport. What is embarrassing for the British government is that both the UDA and the UVF and their political representatives - the Ulster Democratic Party and the Progressive Unionist Party respectively - are pro-agreement.
So far, the feud has been in Belfast only, but there is concern it could spread. The UDP's office in Lisburn, Co Antrim, closed early yesterday - in case of a UVF attack.
"This isn't a UVF-UDA feud. It's a UVF-Shankill UDA feud," says a loyalist source. "Relations between the two organisations in other areas are OK and we are desperately trying to keep it that way."
Although the UVF is widely regarded as the more disciplined and "professional" organisation, it is outnumbered four-to-one by the UDA on the Shankill. Over the past year, the UDA has been actively recruiting, particularly among the young. "In other places, the UDA might bend the knee to the UVF but on the Shankill, it rules the roost," says the source.
The events leading to yesterday's double killing started when UVF members attacked a UDA band parade on the Shankill on Saturday. The UDA then launched two gun attacks on a bar frequented by UVF members and ransacked and burned around a dozen houses.
The UVF retaliated yesterday by shooting dead a man with UDA connections, Mr Jackie Coulter. A man with UVF associations, Mr Bobby Mahood, who was with him, was also hit and died later in hospital. It is understood Mr Mahood was anti-agreement and did not support the policies of the PUP leadership.
Tensions between the UDA and UVF in Belfast have been growing all summer. It began when the UDA Shankill commander, Johnny Adair - recently released from prison - aligned his group with the dissident Loyalist Volunteer Force which is at loggerheads with the UVF. Mr Adair was present during an LVF show of strength on the eve of the Drumcree protest.
Although he has publicly voiced support for the agreement, few believe him. His pro-peace process comments are attributed to the fact that his prison licence could be revoked at any time.
This month, the Shankill UDA has been upping the ante. There were scores of attacks on Catholic families along the peaceline. Mr Adair is said to enjoy his high media profile. There was widespread scepticism about his repo
rts of having survived a Provisional IRA murder attempt last week.
The UDA and the UDP appear divided over Mr Adair. UDP leader Mr Gary McMichael and other moderates are said to be "appalled" by the violence which they have had no control over. They want to build the UDP politically and know recent events could have - perhaps fatally - damaged its electoral chances.
One UDP activist said he was disgusted by the weekend attack on the home of former UVF leader Gusty Spence. "Gusty is a pensioner. For loyalists to do that is appalling."
However, other UDP figures, such as Mr John White on the Shankill, are close to Mr Adair. UDA activists also say that, although many in their organisation have previously been suspicious of Mr Adair, yesterday's UVF double murder could cause them to rally around him.
"We might not agree with everything Johnny does but he is one of us. By killing one of his men, the UVF have attacked our organisation and we can't allow that. Action will have to be taken," says a source.
Mr Adair is a hero figure for grassroots anti-agreement loyalists, but this status has led to fears for his security among his friends.
"Billy Wright was the last loyalist figure to present such a big threat to the peace process. He annoyed the UVF, the Provos, and the authorities and look what happened him. We will have to be very careful," said an Adair supporter. Mr Wright was shot dead by the INLA in the Maze prison in 1997.
Yesterday morning, the Shankill UDA was talking of mediation to end the feud, but the UVF double murder has changed the mood from one of conciliation to revenge. "All bets are off," said a member last night.
The Northern Secretary, Mr Mandelson, said he would not hesitate to act if he was advised the UVF and UDA had breached their ceasefires. But he needed to establish the facts and was not going to jump to conclusions.
He warned that prisoners given early release under the Belfast Agreement could be sent back to prison if they were found to be involved in violence. "Any ex-prisoner who is out is not totally free, they are out on licence and any individual who breaks their licence, they know the consequences of their actions and I will not hesitate to act if I have to."
He urged the people of the Shankill Road and north Belfast to reject individuals and groups of thugs engaged in a "turf war".