The three Real IRA men heading towards Massareene British Army base wouldn't have known what awaited them. As they drove through the countryside in staunchly unionist south Antrim, they would have wondered if the SAS would ambush them before they even stepped out of the car to launch their attack.

The Chief Constable, Hugh Orde, had just said undercover British military intelligence forces had been employed because of the increasing republican threat. The Real IRA could have been driving into a trap. The men would also have known the armed security guards on the barracks' gate could easily return fire. Yet they continued.

So were they lunatics blinded by outlandish ideas which caused them not only to take lives but to risk their own, or did they have a strategy? Last year, I conducted a three-hour interview with two representatives of the Real IRA Army Council.

They were ruthlessly uncompromising but they were certainly not mad. Questions were met with rigorous replies which, however unrepresentative of wider Irish society, fitted the rationale of traditional physical-force republicanism.

"Our goal is the same as the IRA's has always been – to force a British withdrawal. We're no different to the men and women of 1916, 1919 or 1969. Past generations of republicans are always used to condemn the present generation," the Real IRA leader said. "We're emerging from a three-year period of reorganisation in preparation for a renewed offensive."

The Real IRA has undergone internal restructuring in which some members have been expelled and units disbanded in an attempt to tighten up the organisation. Fresh recruits have now joined seasoned activists. The Real IRA had a "new confidence", its representative said. It wasn't frightened to kill, no matter what the security response might be. Massareene would later prove his warning.

I left with no doubt this was a deadly serious and professional outfit. That was also reinforced by the extreme security measures it took in setting up the interview along the border. The Real IRA has nowhere near the membership or support network the Provisionals had. But to claim the entire organisation could meet in a phone box is nonsensical.

The south Antrim attack alone would have involved up to 12 personnel – in terms of those providing the information, lifting the weapons from the arms dump and transporting them to the unit, buying the getaway car, arranging for the other car after the getaway vehicle was abandoned, and providing the safe house for the gunmen in the immediate aftermath.

The Real IRA has an estimated 200 members. Its weapons include a mix of former Provisional IRA arms taken from that organisation and new Eastern European weapons. Formed in 1997 by senior Provisionals who opposed the second IRA ceasefire and Sinn Féin's political direction, it has proved remarkably resilient.

Its death knell was thought to be the Omagh bomb massacre in which 29 civilians were killed. There've been numerous attempts to infiltrate the organisation by MI5, the Garda and the FBI. MI5/FBI agent David Rupert received millions of pounds for his efforts, a payout unprecedented in paramilitary history.

Despite what unionists believe, the Provisional IRA has genuinely tried to crush its rival. Real IRA members have been abducted, beaten and threatened with death. Belfast Brigade OC Joe O'Connor was shot dead by the Provisionals.

The Real IRA is incapable of mounting a sustained campaign similar to that of the Provisionals in the '70s and '80s with attacks on a daily basis. However, even an infrequent campaign with unpredictable shootings and bombings of high-profile targets would put immense pressure on the peace process.

Real IRA leaders know their campaign will not force a British withdrawal from the North in the short- or medium-term. They seem in it for the long haul. Their short-term objective will be to prevent the Stormont administration, or any settlement which falls short of Irish unity, succeeding.

The scenes of security-force snipers and heavily armed police back on the streets will be viewed as a success by the Real IRA because it reverses the normalisation of Northern Ireland society and policing.

Each 'successful' Real IRA attack is armed propaganda for the organisation because of its publicity and recruiting value. Targeting Police Service of Northern Ireland (PSNI) officers raises tensions in the North, while targeting British soldiers brings extensive international publicity. The Real IRA expressed a desire to launch attacks in Britain itself. Whether it has the operational capacity remains to be seen.

The Continuity IRA, which killed the PSNI officer in Lurgan, was formed in 1986 following the split in the Provisional movement over abstentionism from the Dail. Its failure to inflict fatalities on the security force in its 23 year history led many to believe it was moribund. That was not the case.

The Real and Continuity IRA's attacks, within 48 hours of each other, were not co-ordinated as it might seem. Massareene most likely 'encouraged' the Continuity to take action. Although the two groups share similar goals, they've no organisational links and don't mount joint operations as they once did. The pattern of activists floating from one organisation to the other has also stopped.

The Real IRA appears strongest in Derry, south Down, east Tyrone, and Fermanagh but has a wider geographical spread of members than the other dissident groups. Continuity has a presence in north Armagh, Fermanagh, and Belfast. The third dissident group, Oglaigh na hEireann (ONH), a Real IRA splinter group formed three years ago, is strongest in Belfast (where it carries out regular punishment attacks) and south Armagh. The security forces are concerned about the skills of an ONH bomb-maker.

The Real IRA is the largest and deadliest of the three groups. The key to its survival is whether ordinary nationalists pass information to police. During the Provisional IRA campaign, SDLP members and supporters were usually too terrified to do so regardless of what the party leadership might have said. Time will tell whether Sinn Féin's attempts to encourage nationalists to give information following republican attacks succeeds.

The Real IRA refuses to accept that the Provisional IRA campaign failed militarily.

It contends there was ample weaponry and activists but a Sinn Féin leadership, more interested in winning elections, manoeuvred a decline in the armed struggle and even prevented the use of a significant amount of Libyan arms. The Real IRA boasts that it is answerable to no political party.

It's difficult to see how it can be talked or tempted into the peace process. Its conviction that the bullet, with no accompanying ballot box, is the best way forward, seems unshakeable as does its 'Brits out or nothing' political position.

For years, the Provisionals had contact with the Dublin government through west Belfast priests; and with MI6 through Derry go-betweens, Denis Bradley and Brendan Duddy. When I raised the issue of direct or indirect talks with London or Dublin, the Real IRA said they'd no interest in dialogue "through Bradley, Duddy or any Redemptorist priests".

Encouraging the Real IRA in from the militant margins looks impossible. The people I interviewed didn't seem the type to be wooed by the possibility of one day securing White House invitations.