Republican vigilantes conducting a campaign of shootings and beatings have in the past year forced more than 200 young men out of Derry, which will become Britain's City of Culture in 2013, the Guardian can reveal.
At least 85 men have been shot over the same period in "punishment" attacks by Republican Action Against Drugs (RAAD), according to police figures.
In some instances those targeted, mostly in their teens or early 20s, have been forced to turn up with a parent or relative for a pre-arranged appointment to be wounded for alleged drug dealing and other supposed crimes.
Martin McGuinness, the Provisional IRA ex-chief of staff turned deputy first minister of Northern Ireland, made an unprecedented move calling on the public in his native city to inform on the republican paramilitaries responsible. Figures from community organisations in Derry mediating between RAAD, the Real IRA and the victims show up to four men are being forced out of the city every week.
As Derry prepares to be the UK's City of Culture, the families of those under attack, including the mother of a RAAD victim who was murdered in February, say they are existing "in a city of fear".
Derry-based John Lindsay, author of "No Dope Here", a new book on the violence, who has shown his research to the Guardian, said: "On average there are about four young men being forced out of the city by RAAD and other vigilante groups per week.
"The figures are being recorded by at least two community groups who are called into liaise between the organisations and the men.
"There are, on a conservative basis, more than 200 who were put out of Derry over the last 12 months. They are going to places as diverse as Belfast, Armagh, Dublin and of course England, anywhere where they have friends or relatives to flee to. And they are told if they don't leave they will be shot or even killed."
The vigilante campaign turned murderous last February when RAAD gunmen shot dead a former Derry boxer, Andrew Allen, 24, just across the border in a relative's house in Co Donegal. His family say hardline republicans were so affronted when he stood up to them that they decided to kill him. Allen's mother, Donna Smith, said the peace process no longer meant anything to her or her family.
"How can they call this the City of Culture when they (RAAD) are going around butchering children? Something has to be done, it has to be stopped before another family is sitting in the situation that we are in: me without a son, my other children without a brother and two small children without a father."
There have been several demonstrations against the attacks, including one last month. Just before, an 18-year-old was shot in both legs.
Although some RAAD members are ex-IRA members who supported the end of its "war" against Britain and declined to join the anti-peace process Real IRA, McGuinness has issued his sternest condemnation yet of the vigilante campaign.
He said: "I think it is quite obvious the community is beginning to rise up against this and as a result of that it is quite clear that RAAD are about to make the biggest mistake of their lives. They are about to bite off more than they can chew because if the community in Derry turns against you then you are going absolutely nowhere.
"And I think they (RAAD) do need to be going somewhere and they need to be going to prison. And I would hope as a result of the rise in opposition to the activities of RAAD that people will come forward to give all the information they have about this group."
McGuinness, the Provisional IRA's second-in-command in the city on Bloody Sunday, described the republican vigilantes as "the new oppressors of the people of Derry".
The police have vowed to prosecute those responsible. However, there have been no prosecutions for the "punishment" attacks" and no one has been charged in connection with Allen's murder.