Real IRA, Real Life

The truth is written on the walls, says Mark, an officer in the Police Service of Northern Ireland who is mourning his murdered colleague but does not believe what the politicians are saying.

"We keep hearing people at an official level insist the killers are isolated and have no support from the community," he says, and the message has been repeated often since a policeman and two soldiers were shot dead last week. "But we know that it is not true. Not a single person at ground level really believes it. Everybody knows there is support for them."

For evidence, he points to the walls of the housing estates in County Down close to where Constable Stephen Carroll was shot on Monday. Not just the stencilled images of gunmen right by the murder scene, provocatively flanking the words "Still At War", but also the crossroads in Lurgan, within walking distance but away from the camera crews, where the lamp posts are painted orange, white and green.

At least one of three men arrested yesterday for the killing of the soldiers comes from Lurgan. The bus stop has been sprayed with the initials of the Real IRA. A red circle with a line through it, of the sort that usually says dogs or bicycles are banned, condemns the sell-outs of the Provisionals, the ones who traded their arms for peace. Words sprayed alongside a wasteland say: "M16 Gun Kills British Scum".

These are not the murals the tourists come to see, the icons of the Troubles that seemed safe to enjoy as historical artefacts until the murders last week. These are scrappy, nasty, tatty messages, says Mark, but they reveal what is really going on. "The official story," he says, "is not the whole story."

He does not want his real name to be used because he is keenly aware of defying the official mood this weekend. Old enemies are putting up a united front, freezing out what the former IRA commander Martin McGuinness, now deputy first minister, called "traitors to the entire island of Ireland". Last night a prayer service was held in the car park opposite the Massereene barracks in Antrim where British Army sappers Patrick Azimkar and Mark Quinsey were shot seven days earlier. The three men arrested yesterday were aged 41, 32 and 21 and came from Lurgan and Bellaghy. They were being questioned at Antrim police station.

With St Patrick's Day celebrations coming on Tuesday, the hope is that the killings will prove to have been the actions of a few nostalgics and nothing more. The future depends on it, and particularly on loyalists believing it so much they do not respond with violence.

The story told by the tourist board to those who come for this week's shamrock-strewn parties is one of success and transformation – and there is much to celebrate. Peace and prosperity have lasted more than a decade and it shows. Glorious old buildings have been restored and new ones built; money has poured in from the European Union; jobs have been created across the province; cafés and posh restaurants have opened. Tourists come for the beautiful countryside, the culture and the night life in Belfast, which is resisting the recession as the weak pound attracts visitors from the south. It has even learnt to market the signs of strife such as graffiti and murals, presenting them as signs of the past, as harmless as the shipyards where the Titanic was built. But the real Northern Ireland, whose real but relative peace is now threatened by the Real IRA and other dissident groups, is a much more troubled place than the glossy brochures suggest.

They fail to mention that the high, concrete and steel peace walls running through Belfast are not a historic attraction but a way to stop people from fighting each other right now. The city has 40 peace lines, which it stuns visitors to learn is nearly twice as many as when the Good Friday Agreement was signed over a decade ago. The separation of Protestants and Roman Catholics is still institutional in Northern Ireland: all but 5 per cent of children are educated in segregated schools, which a celebrated former pupil described last week as "a form of apartheid". Surveys show that most parents would like to change it, but also that one in five would not.

Here, peace meant the absence of funerals but not the absence of shootings, assaults, arson attacks, petrol bombs and explosives. Even as a vigil was being held in Londonderry on Wednesday, homes and offices were being evacuated because of a suspected bomb. It was found next to scrawl that said: "RIRA 2 Brits 0". Words daubed on a shop front, after the two soldiers were killed as they took delivery of their supper, said: "Your pizza's cold! Two down."

In Craigavon, where Constable Carroll died, the local newspaper said people "joined together to speak with a single voice" in opposition to his murder. Fine words, but not true. Yes, there was a candlelit vigil. Flowers were laid. But after a teenager and a 37-year-old man were arrested (they are still in custody, and a third man was taken in for questioning on Friday) there was also trouble: wheelie bins were set on fire to stop traffic and the flowers were vandalised. Most local people felt revulsion at what had been done, but the killers were acting out the visible desires of those who had written the graffiti and burnt the bins. That just couldn't be said.

And the silence was not just in Craigavon. As the Belfast writer Fionola Meredith said last week: "We've been colluding in the same comforting fiction, that Northern Ireland has undergone a radical and complete transformation, morphing almost instantaneously from war-torn and intrinsically sectarian pariah state to 'world-class destination'." That was wrong. "We've been behaving like Northern Ireland is normal. It isn't."

Taking a £25 guided tour of Belfast in the wake of the murders smashes any idea that this is like any other revitalised British city. First stop is the Shankill Estate, heartland of loyalism, to see the murals on the ends of the drab council houses: Oliver Cromwell, King Billy and so on. The guide, John – "No surnames please", a common refrain – gives the history but cannot ignore the huge image of a man in combat fatigues and a balaclava, or the brightest mural, a memorial for "military commander" Stevie McKeag of the Ulster Defence Association, who died only in 2000. "He was called Top Gun because he killed so many Catholics," says John, reluctantly. The flowers and wreaths laid at the foot of this image are fresh. He is clearly still a hero to some.

The Independent Monitoring Commission says the UDA is still involved in "drug dealing, extortion, money laundering, loan sharking and the sale of counterfeit goods", but trying to wean itself off violence. Prominent loyalists have resisted revenge attacks for the recent killings, but fear what "clowns" might do in their name. Loyalists have been responsible for some of the 23 murders and two-thirds of the 457 assaults carried out by paramilitaries in the past five years. But then republicans were responsible for most of the 374 shootings.

The Real IRA, which claimed responsibility for killing the two British troops, planned to blow up soldiers in County Down in January with a 300lb car bomb. The police were tipped off that it had been left miles from the barracks, outside a school in the village of Castlewellan, where it was found after a five-day search. Security chiefs knew a similar device had been planted in Banbridge only days before the Omagh atrocity in 1998. Yesterday the political wing of the Real IRA, the 32 County Sovereignty Movement, said its war would not stop until Britain ended its "illegal" claim on Ireland. The Real IRA planted explosives under vehicles, in a restaurant and several shops last year; an off-duty PC was nearly killed by a device under his car in County Tyrone.

The Real IRA is also involved in drugs, smuggling, fuel laundering (producing petrol and diesel illegally) and robbery. So is the Continuity IRA, whose members made repeated attempts to kill or maim police officers in the past year. The shooting of PC Carroll was less sophisticated than the barracks killing, but suggests the rival factions are spurring each other on, if not co-ordinating attacks.

One of those being questioned in Craigavon is 17 years old, so can have been only five when the Good Friday Agreement was signed. "Teenagers don't see the historical picture or know what it was like," says the policeman, Mark. "They only know that people who shot and killed in the past were heroes in their local area."

An official stop on the tour is the official headquarters of Sinn Fein. New graffiti went up last week on the Falls Road Library next door: "Fuck you and your pizza. Brits out." But it was quickly painted out. Sinn Fein rules here. The other kind of republicanism is far from the tourist trail, and the money.

In Craigavon, half an hour's drive away, local politicians insist that the constable's killers had no local support, but events in the past year suggest otherwise. In January a gang of masked youths armed with hammers and petrol bombs hijacked an Ulster bus, leaving it burnt out on a roundabout. They were thought to be trying to start a riot, as in October when vehicles were hijacked, shots were fired and fire crews attacked.

Republican Sinn Fein, the political wing of the Continuity IRA, included the riots in its calendar for 2009 under the caption: "A new generation taking on the Brits". The local SDLP assembly member Dolores Kelly said youngsters had been trained in advance: "Police spotted schoolchildren on the Kilwilke estate in Lurgan practising throwing petrol bombs."

Why? Daniel, a youth worker, said: "We have a hot-blooded youth here in Northern Ireland. They only see the glamour of the olden days. They want to identify with something that is rebellious. The older people will tell you that history repeats itself: that the original IRA became respectable, and the Provisionals arose out of that. There is a very real danger that it is happening again. The Real IRA and the Continuity IRA are so disorganised, but all they need to do is get their act together and we really will be in trouble."

That is why important people repeat the official line every day, saying that the killers have no support: because even if it isn't true now, for everyone's sake, it must become so.