In both Ireland (both sides) and England, it is considered extremely offensive, when using this term, to not speak of it with a capital "T". You say "the troubles", they say the Troubles. At its peak, you could get shot at if you walked down the street holding the wrong flag. And there are still many parts of Northern Ireland that blatantly display the Union Jack, and have its colors on bunting and painted on their kerbs, 24/7/52.
Lasting between 1966 and 1998, the Troubles refers to a period of terrorist activity within both Northern Ireland, which sometimes bled through Britain, the Republic of Ireland, and even occasionally in continental Europe. This was a time when the Ulster Loyalists, mostly Protestant (i.e., Church of Ireland, Presbyterian and Methodist), and the Irish Republicans, mostly Roman Catholic, fought each other over which country Northern Ireland should belong to, with the former favoring the United Kingdom, while the latter the Republic of Ireland.
Of course, there are other titles: "Loyalists" are sometimes called "Unionists" or "Royalists", and the Republicans as "Nationalists". The terms are pretty ambiguous, particularly the "Loyalist" title, while "Royalist" implies fealty to the House of Saxe-Coburg Gotha/Windsor (which the Irish Free State did). On the other hand, it's not uncommon for someone to become a "Republican Unionist" (i.e., desirous of democratic rule from a republican Britain), or an Ulster Nationalist (i.e., desirous of an independent Ulster), which does exist. Yes, this really is one of those conflicts, happening right around the corner.
It is a reasonably popular setting for media and a good place to source Western Terrorists from, even today. That British security services got into some shady dealings, factual or fictional (e.g., collusion with loyalist paramilitaries, internment, murder, bombing, framing of innocent victims, black propaganda, political assassination, a shoot-to-kill policy, raiding of homes, the jury-less Diplock Court system, tear gas, surveillance, torture, forced deportation, and kidnappings) adds to the potential drama. Expect knee-capping and bad Irish accents.
If an organization is listed as simply "the IRA" in anything set after The Seventies, then it refers to the Provisional Irish Republic Army, or "Provos", as they are often called (the IRA "proper", though not actually the oldest group with that name). There are several splinter groups and fictional ones are often invented for movies.
While violent, as conflicts go, one might think it was fairly low-key, with an official body count of 3,526... but remember, this happened in a country with a population today of only 1.6 million. The vast majority of the British Army ended up doing tours in Northern Ireland, and this has created its own body of literature (see below).
Not to be confused with the even more violent all-island fighting of 1919-1923, also called the "Troubles", seen in such films as Michael Collins, The Wind That Shakes the Barley and Ryan's Daughter — a fairly popular setting in its own right. It was this conflict that resulted in the creation of the Irish Free State which eventually became the Republic of Ireland.
Due to large numbers of Irish immigrants and their descendants in the USA (about ten times as much as there are back in the Emerald Isle), the American media often saw the Troubles through a slightly green-tinted lens. This extended beyond the media — as late as a decade ago, some American groups were giving the IRA funds, which predictably dried up in the wake of 9/11, when the idea of funding terrorist groups became frowned upon, and ultimately contributed to the group's disarmament. As such, while seldom explicit, the image of the noble Irish freedom fighter struggling against the stuffy (and occasionally baby-eating) British establishment does pervade some films.
Of course, while London did commit actions it shouldn't be proud of, the conflict was hardly as black-and-white as some would rather have it, and is more or less like a real-life case of Grey and Gray Morality (Britain was only responsible for 10% of the total casualties, compared to the republican and loyalist militias' 60% and 30%, respectively). Even when the media in recent years increasingly cast the IRA in a darker light, being a stock source of Western Terrorists, it is wise to remember that both sides equally have a fair share of blood on their hands.
Often, a heroic character explicitly belong to one side will decry the excesses of his comrades and/or leave in disgust after they wenttoofar (expect this to involve deaths of children, a tragically all-too-common result of tactics used by both sides). Purely villainous groups of terrorists are often said to belong to some fictional Renegade Splinter Faction, in an attempt to avoid political controversy. Sadly, there really are splinter groups (such as the "Real IRA") determined to continue the violence.
The Troubles are pretty much over now, with the IRA having effectively ceased to function, although there are still occasional flareups (some as late as 2009), and sectarian violence, largely unrelated to the conflict, still rear its ugly head (though the recent credit crisis led to both factions joining together... to riot against Romaniand Eastern Europeans. The legacy remains, though — a recent proposal by a commission to pay the nearest relatives of all casualties a compensation of £12,000 led to outrage. Also, a lot of former IRA men are now involved in drug rings, partly because smuggling guns during that period turned out to be rather good training for drug running, and the IRA once trafficked drugs as a source of ready income. On the flip side, they've made great training for teaching the British Armed Forces to deal with potential threats. You can find a short history of the conflict in this folder:
The Sordid History of the Troubles
It is likely that, but for want of compromise and moderation on both sides, the Troubles might never have become what they were; like that other long-running dispute people get heated up about to this day, it treads the fine line between tragedy and farce. As the sorry narrative shows, there's clearly a shortage of level heads in the Six Counties — history records few conflicts guided so much by passion and so little by reason (or to be perfectly blunt:almost everyone who counted acted like morons for over half a century).
The Troubles has its roots in The Irish Revolution. At the end of the aforementioned war, the United Kingdom decided to divide Ireland between an independent state for the predominantly Roman Catholic south and a constituency of the Union for the six Protestant-dominated counties to the north, even as this proved unpopular to either side, which wanted the entirety of Ireland for their respective political entities. For the next forty years, the loyalists alone ruled Northern Ireland, while the Catholic minority was largely excluded from public life by snobbery, poverty and bigotry. The Union government, happy to be finally shorn of The Irish Question, washed its hands of the affair, and this system persisted for years.
Up until The Sixties, Belfast had a wide latitude which it often abused. Anti-Catholic gerrymandering was common. The great shipyards of Belfast, such as Harland and Wolff, were closed to Catholics, and inequality in allocation of council housing and healthcare was institutionalized. This had long been a source of official disapproval from London, and Harold Wilson, then Prime Minister of the Union, pressed his Northern Irish counterpart, Terrence O'Neill, to cut back on discrimination during a 1964 visit. O'Neill gave him some pleasant words and made some token moves toward reform. But even these inspired Protestant fury, and progress was very slow. O'Neill's government collapsed under loyalist wrath, and a weaker government under James Chichester-Clarke was formed, which was too timid to push forward with reform, forcing Wilson to give an ultimatum: get going, or else. Whether Britain's intervention is more a case of political pragmatism or genuine concern depends on one's views.
In 1969, the Catholics formed an active civil rights movement, partly inspired by that which occurred years earlier just across The Pond. At the same time, a loyalist mob called "Apprentice Boys of Derry" planned a counter-march on the same day and route as that by the civil rights activists. This went as well as expected — the latter, ordered not to march, marched anyway, and were attacked by loyalist police. There followed some of the most shocking scenes of Police Brutality ever seen in the British Isles, especially from the infamous B-Specials, an unpaid and part-time adjunct to the regular police force. Enraged, the Catholics went into hyperdrive, marching and protesting... and being attacked again and again. In response, and likely due to prodding from an indignant London, Belfast promised wide reforms... which led to even more loyalist belligerence. At the beginning of August, there was a serious three-way riot between both sides and the police in the center of Belfast. MP J. Enoch "Rivers of Blood" Powell even suggested deporting the entire Catholic population to the Republic. Appalled, Wilson and then Home Secretary James Callaghan took the decision (without consulting the Cabinet) to send in the British Army to restore order in return for the abolition of the B-Specials and serious reform. It is a myth that they were not aware of the dangers (they estimated that it would take at least a decade before they pulled out), and some historians have called the decision to send in the Army "Jim Callaghan's finest hour."
Alas, this caused more harm than good. The IRA, then just a small faction, spread untrue (at the time) rumors that the Army was colluding with loyalists, whilst loyalist paramilitaries feared losing their "privilege". For more extreme republicans, the very presence Brits was unforgivable. Fortunately, there were signs in the next two years that the situation would pass... until the worst possible scenario in the eyes of London became a terrible reality.
One Sunday — January 30, 1972 — the Parachute Regiment, for reasons unclear still, fired on marchers in Derry, killing two, causing republican snipers to retaliate with a (missed) shot, causing the panicking paratroopers to fire indiscriminately into the crowd, killing eleven more and wounding several others, one of whom later died from injuries. This was "Bloody Sunday", the Darkest Hour of the conflict and a black eye to the face of the British Armed Forces. The tragedy led to a surge in popular support, at home and abroad, for the IRA. Whole sections of Derry declared themselves "free", rejecting British rule and attacking any official representative that dared trespass. Money started flowing in from American donors. The communist bloc, seeing an opportunity to harm Western interests and destabilize a critical American ally, began funding other republican groups. Later, in revenge for the US bombing of Tripoli (launched from British bases), Muammar Gaddafi joined in the fray. In response, London took swift, decisive and sometimes brutal action. The IRA developed the "colonial strategy", that is, to make Northern Ireland ungovernable save as a de facto imperial colony, the result of which would be to turn the international community against Britain. So began the long and squalid history of the Troubles.
Violence increased through The Seventies and The Eighties, with IRA bombings, loyalist killings, and shootouts between the British and both sides being a common feature. The Army, previously deployed to keep order, now found itself fighting for the survival of the United Kingdom itself. Faced with escalating violence, crackdowns became more severe — tanks were used to restore order to "free Derry", while elements of security forces colluded with loyalists. Many of the controversial features of The War on Terror — the renditions, the torture, detention without trial, and the like — saw their bloody precursors here. Gradually, both sides became more extreme. The IRA now began targeting civilians (as opposed to military installations back in their earlier years), and began a tit-for-tat cycle of violence against loyalists, with casualties being reported by the day. Riots were common, and a Berlin-style system of walls and checkpoints was enforced in Belfast and Derry to keep the feuding communities apart. The IRA became ever more brazen, killing Louis Mountbatten, 1st Earl Mountbatten of Burma, war hero and mentor to Prince Charles, on his yacht off the coast of County Sligo in 1979 (and it's something of a Shoot the Shaggy Dog story — Mountbatten was favorable to the Irish cause), and nearly doing in Margaret Thatcher, then in Brighton for a 1984 Tory convention (though with five deaths). However, there were signs of hope for a peaceful solution, too: In 1985, the Anglo-Irish Agreement gave Dublin a "consultative role" in the government of Northern Ireland. Fearing that they were being "sold out", some loyalists, armed by their stooges in the Ulster Defense Regiment and weapons dealers in Africa, began a campaign of terror in response.
By the early 1990s, both sides had seen enough. John Major and Sinn Fein, the political wing of the republicans, agreed to a ceasefire in 1994. The USA also decided to act as mediator, to which both sides agreed, with Bill Clinton personally acting as middleman in 1995, to the delight of both sides — an oft-forgotten (at least in the USA) triumph for his presidency. He helped lay the foundations for an end to the bloodshed. The Troubles might have ended then and there, but it was not to be. London refused to negotiate until the IRA decommissioned (or at least lay down arms), which the IRA flat-out refused to do (because Major's government had a very weak majority, and was dependent on loyalist backing to survive). In 1996, the IRA bombed Canary Wharf in London, breaking the ceasefire. More bombings followed, including a massive blast in Manchester which failed to kill anyone but destroyed the city center. Finally, due in part to political maneuvering by the British (who started separate negotiations with other republican groups), American intervention, and a series of successes in halting arms and cash flow, Sinn Fein and the IRA agreed to disarm. During this process, the Real IRA, an extremist republican splinter cell opposed to the treaty, bombed Omagh, killing 28 civilians, provoking disgust on both sides and hastening moves for peace.
The Good Friday Agreement was signed at Stormont in 1998, and a devolved Northern Irish administration was established, where republicans and loyalists could settle their differences at the ballot box. British troops left Ireland, leaving behind the 19th Light Brigade, which has no operative role. In one of the rare Pet the Dog moments, a Republican mural in Belfast bade the troops "Slan Abhaile" ("Safe Home"◊). The IRA formally declared an end to its armed campaign in 2005, having decommissioned its weapons in that same year. The Tony Blair cabinet agreed to hold an inquiry into Bloody Sunday. The largest and costliest investigation in British legal history, it delivered its final verdict in 2010, declaring that the paratroopers defied orders in entering republican patches of Derry and acted unlawfully in opening fire. David Cameron delivered a formal apology on behalf of the British government, to applause from Republican crowds in Derry.
Today, sectarian divisions still persist in Northern Ireland, and it is just as divided as it was in The Sixties. A few furious holdouts still try to maintain a campaign of terror, but for the most part serious violence has subsided. The area still has many problems, including sectarian violence, but many British and Northern Irish are optimistic that, in time, these wounds will finally heal. As a new generation that knew nothing of the violence and hatred of the last few decades grows, the Troubles can be hopefully consigned to history. The long-term dispute at the center of the Troubles, the question of Irish unification, seems to be diminishing in relevance, with recent surveys suggesting that it is increasingly becoming less of an issue than it was decades ago, though this likely as as much (or more) to do with the economic crisis in the Republic as it does developments inside Northern Ireland itself. Whatever Northern Ireland's future, one can only hope it will be better than its past.
In Mobile Suit Gundam 00, the first sign that Celestial Being were having a palpable effect on the world was the ceasefire message sent out by the "Real IRA" group in Ireland. Considering the show is set in the 2300s, that's a seriously persistent splinter group.
The 1997 Nights into Dreams comic book featured the eponymous dream-whatever fighting Irish terrorists.
Belfast-born comic writer Garth Ennis has mined the setting for all its worth, starting from his earliest strip Troubled Souls. His views on Irish-Americans who supported the IRA can be seen in a Punisher story where one such man spots an evil disfigured terrorist (thanks to an "own goal" premature detonation) and gets the whole bar to raise a glass to the man's struggles... which directly leads to him being used as a hostage and human shield by said terrorist.
There was also an issue of his "regular Marvel continuity" Punisher ongoing that had the eponymous character go to Northern Ireland and end up shooting an extremist from both sides in the kneecaps, yell at them and then leave a Kalashnikov automatic rifle before them. Unlike the usual recipients of his bullets he let them live... only for them to decide that they wanted to use that rifle against each other. Though he'd planned it out that way, leaving it with no bullets, knowing they'd bleed out before even reaching it.
Both the IRA and the loyalist militants turn up as frequent enemies of Kev, Ennis' ex-British S.A.S character, who was demobbed after various activities during the Troubles that earned him a death sentence from both sides and who routinely send assassins out to kill him. Unfortunately for Kev, they have a tendency to surprise him just when it's most inconvenient for him (when he's sitting on the toilet, having sex or on A Date with Rosie Palms). Unfortunately for them, they're either spectacularly incompetent, outclassed by Kev despite these handicaps, or attack him at the same time as one of their bitter enemies, resulting in them just killing each other instead.
For that matter, Cassidy from Preacher fought in the Irish War of Independence (the other 'The Troubles' alluded to further up the page), and has a number of not-too-kind words to say about the whole ordeal.
Of course, the sequel also gets it wrong, being set in 2003, while The Provos broke apart in 1998. The "Real IRA" has a tendency to set itself apart from the Regular IRA, which many members consider 'quitters'.
Slipping Between Worlds is set partly in Northern Ireland at the height of the Troubles, and partly in the Discworld. It is believed the author is drawing on (slightly embellished) direct personal experience of having served in Northern Ireland in the early 1980's. The author has said his reasons for writing this include breaking away from a mere pastiche of Terry Pratchett and seeking to find his own voice as an author. Reading about the bitter mutual antagonism between Dwarfs and Trolls on the Discworld made him link back to Northern Ireland and his experiences there, and to the realization that there are more similarities between N.I and the bizarre distorted-mirror Discworld than might be apparent at first glance. The Northern Ireland scenes are written with a certain black humour characteristic of British soldiers, but also with restraint and a certain sympathy for the people of N.I. The author stresses he was seeking to avoid giving gratuitous offence, expressing any bitterness, or trivialising of the issues. Among other highlights, an account of a memorial service for six dead British soldiers sticks in the mind. This is apparently part-based on reality.
Ronin: When Seamus O'Rourke is killed and the briefcase lost by the Irish faction, it leads to an IRA ceasefire.
Bloody Sunday, an acclaimed TV film turned cinematic film and one of many works on the eponymous topic, the shooting of 13 people by British soldiers (the inquiry on which finished in June 2010, 38 years after the event). A demonstration on why it is not a good idea to do riot control using pissed off military types and live ammunition.
It turns out that the hero had been the villain's friend and protege (and was even dating the villain's sister). The villain sought revenge because the hero had attempted to stop one of his bombs from going off as it was near children, resulting in the death of the sister/girlfriend, the imprisonment of the villain and the hero fleeing to America to start a new life.
Both the movie and comic of Sin City has a group of IRA terrorists that mention blowing up churches and pubs. Apparently, they now act as mercenaries for the mob in America. Bonus point: one of them is depicted with a Glasgow Grin.
In The Name Of The Father, a dramatization of the Guildford pub bombings in England by the IRA and the torture, threatening, and false imprisonment of Gerry Conlon, the young men and women he was staying with in London, and his father and a handful of family members who were falsely convicted of providing the explosives. The film opens with a riot in Belfast and Gerry accidentally fleeing through an IRA weapons stash, resulting in him nearly being kneecapped as punishment.
Hunger, starring Michael Fassbender, is about the the 1981 hunger strike of IRA inmates to obtain political prisoner status.
The titular heroes of The Boondock Saints are supplied with their weapons by an arms dealer who's heavily implied to be involved with the IRA.
The Kevin and Sadie young adults novel series involving the forbidden love between a Protestant (Sadie) and a Catholic (Kevin), the first book of which was titled The Twelfth Day of July (the day of the annual Orange Marches, some of which usually end up in a riot even today, and did in the novel). The most famous is the second (of five) in the series, "Across The Barricades".
Tom Clancy's Patriot Games draws his regular characters into the whole mess when Jack Ryan saves Prince Charles and his family from an assassination attempt by the Ulster Liberation Army. In the novel, the ULA is a Marxist splinter faction of the Provisional IRA. In fact, the ULA's actions often contradict the Provos own mode of operations. It turns out the ULA's goal is to eliminate or discredit the PIRA leadership, and have their leaders take over. Clancy also used the PIRA in Rainbow Six, being hired by the villains in an attempt to take out the Rainbow team.
Forms the subject of a George Gently mystery, set in 1964. An MI5 character warns that unless London does something about disgruntled Catholics in Stroke Country, it will result in a war. Oh, how right he was.
Jack Higgins (of The Eagle has Landed fame) loves to use The Troubles (and the preceding 50 years of hostility) as background and motivation for his antiheroes. He favours cynically disillusioned IRA gunmen, but doesn't limit himself.
Jonathan Coe's The Rotters' Club has occasional mentions of the IRA bombings going on in the Midlands at the time. Then the protagonist's sister and her boyfriend are caught in one. He dies, and she goes into Heroic BSOD for several years.
Bernard MacLaverty is a writer from Belfast, so this comes up in his work now and then...his 1983 novel Cal, in which the title character deals with some of the fallout of having driven the getaway car for one of his buddy's IRA actions a year earlier, was made into a film starring Helen Mirren and John Lynch.
Alan Judd's debut novel A Breed of Heroes sees the Troubles through the eyes of a naive young officer in the British Army, Charles Thoroughgood, on his first tour of duty with an elite unit which is never identified but which can be inferred to be the Parachute Regiment. The multiple absurdities, hypocrisies and bungles of the Army, politicians, terrorists, media and others pile up throughout, while the focus is always on the privations and everyday lives of the often-forgotten soldiers.
George MacDonald Fraser, in the third of his semi-autobiographical short story collections, The Sheikh and the Dustbin, adds a postscript concerning later meetings with his former commanding colonel, forty years on from their post-war soldiering in 1947-48. This extraordinary old man, a prisoner of the Japanese for most of WW2, in his early eighties donned Army uniform and a flak jacket and went out onto the streets of Belfast with a patrol from the Gordon Highlanders, to get an idea of the difficulties presented to the young soldiers of his old regiment in a new age...
In Andrew M. Greeley's novel Irish Gold, Chicago author Dermot Michael Coyne teams up with an Irish college student, Nuala Anne McGrael, to translate the diaries of his grandmother, who emigrated from Ireland during The Troubles, possibly because she knew the truth about the murder of Michael Collins. According to the novel, Collins was killed on orders of Winston Churchill.
Diana Wynne Jones story "Dogsbody" was set during the very peak of The Troubles, with a small Irish girl called Kathleen being the daughter of an imprisoned Loyalist terrorist. During the story, her father escaped prison, and was subsequently murdered by Republicans. Her father however played no role in the story besides his death.
Spooks has featured various ex-IRA terrorists during its run, including a splinter group similar to the 'Real IRA' in series 1's Cliff Hanger. Harry's back story is that he got into intelligence work when serving with the Army in Northern Ireland.
In the JAG episode "Trinity", Harm and Mac go to Belfast to investigate the disappearance of an infant child whose mother is an American naval officer, and the father, who is an active member of the IRA.
An episode or two of NCIS has someone who worked with the IRA leave and run guns in other places after "peace broke out." (For bonus Irish accuracy points, she travels under the name "Grace O'Malley".)
As in the NCIS example above, Burn Notice's Fiona is a former IRA explosives specialist who's gone freelance in recent years. Funnily enough, when the show began airing in the UK, Character Development revealed that she left the IRA upon realizing her idealism wasn't as welcome in the group as her ability to blow shit up.
Dr. Cal Lightman from Lie to Me worked with British intelligence in the province in 1986. He failed to recognise the facial expressions of a man who then killed six people in a pub.
We learn more about that in "Sweet Sixteen". Turns out the man (Jimmy Doyle) really was IRA, but because Cal identified him, the Do D (American Department of Defense) carried out a hit on him that failed and killed his wife and daughter instead. He blackmails Cal into finally bringing the case to light seven years later.
In the 2001 The Bill spin-off Mini Series, Beech Is Back, Dirty Cop Don Beech used a recognized IRA bomb threat codeword to lure police away from where he was executing a safety deposit box robbery.
An early episode of Law & Order focuses on the Troubles from the U.S perspective; there's plenty of sympathizers to the cause amongst the Irish-American community depicted, including one who's actually a member of the IRA. Prosecutor Ben Stone, an Irish American, is notably not one however.
In Sons of Anarchy the club has longstanding ties to the IRA. It buys its illegal weapons from an IRA splinter group and Chibs is a former IRA member who was exiled to the US. In Season 3 they go to Belfast and end up in the middle of a conflict between two factions of the group. The faction the Sons usually deal with has turned more and more toward organized crime and the other, more conservative faction wants them purged.
Unsub Ian Doyle from Criminal Minds turns out to be involved with the IRA; he tries to kill everyone who put him in jail (and almost succeeds.)
A critically acclaimed play by BBC Northern Ireland about the troubles was called The Shadows on Our Skin and took its title and incidental music from Irish celtic-rock group The Horslips.
The IRA is pitted against the Taliban on the season 1 finale of Deadliest Warrior. The IRA win.
In the final episode of the original Columbo series, "The Conspirators", the villain is an IRA gun-runner named Joe Devlin, played by Clive Revill. He's portrayed as a philosophical Knight Templar, who works as a poet and author in his legitimate life. He also raises funds for an organization called American Friends of Northern Ireland, which is more-or-less an Expy of Noraid (with the fact that the money really goes to the IRA being less of an Open Secret than in real life). The requisite murder is of an Arms Dealer, who was planning to take Devlin's money and flee the country.
The 2013 BBC Northern Ireland series The Fall features a London detective superintendent being sent to Belfast to help the local police track down a serial killer, with the Troubles providing a constant backdrop (including a memorial plaque to police officers murdered during the conflict displayed in their headquarters).
Oz had an IRA terrorist, Padraic Connelly, put into the titular prison while awaiting deportation to the UK. The Irish-American Ryan O'Reilly palled up with him and basked in the reflected glory... until he discovered that Connelly was completely Axe Crazy and planning to blow up the entire prison wing.
In Silent Witness Sam's father was thought to have been killed by an IRA car bomb. The revelation of the truth behind his death was what made her leave her job and the series.
Call the Midwife: Although set several years before the "proper" beginning of the Troubles, Series 3, Episode 6 reveals the, erm, trouble brewing in NI with the Doyles, who eloped from Belfast to London because he was Catholic and she was Protestant and in 1959 there was no way their families would ever let them get married.
Tommy Sands' famous "There Were Roses," is about a true incident from the Troubles involving two of Sands' friends.
The U2 song, "Sunday, Bloody Sunday". The most famous live performance of it is in Rattle And Hum when Bono denounced the Irish-Americans who ignorantly cheered the bloody partisan violence in Ireland.
And the John Lennon song of the same name, written almost 10 years earlier.
Northern Irish punk band Stiff Little Fingers early songs were frequently about The Troubles, although they supported neither side and decried violence from all terrorist groups, the RUC and the British Army.
Richard Thompson's song "Guns are the Tongues" seems to be about a female provo cell leader seducing a young man into becoming a terrorist, though he's deliberately avoided confirming the hypothesis in interviews.
Paul McCartney and Wings' 1972 single "Give Ireland Back to the Irish". Despite being completely banned from UK radio, it reached the Top 20 on the charts there and went all the way to #1 in the Republic of Ireland (no surprise there) and Spain (after being bought by Basques).
The Roches' song "The Troubles" is about the group visiting Ireland, presumably while on tour, and includes a line about trying not to get in the way of the guns.
The Decemberists' "Shankill Butchers" is a particularly nightmarish song about the eponymous gang of UVF thugs who ended up just killing anyone they wanted (Catholic or Protestant).
The Cranberries' "Zombie" is half the troubles, and half just how much war sucks.
Elvis Costello's "Oliver's Army". The title refers to Oliver Cromwell, who formed the modern British Army and invaded Ireland in 1649. It also refers to the British Army occupation of Northern Ireland at the time the song was released in 1979.
Gary Moore, Irish-born rock-blues guitarist, recorded a powerful song called Wild Frontier (Forty Shades of Green) about growing up in Belfast in the Troubles.
Many Irish traditional songs are thinly-disguised allusions to the fight for independence from the British. Thin Lizzie's first hit, Whiskey in the Jar (a traditional Irish folk song), is on the face of it a song about a roguish highwayman whose luck runs out and who is awaiting execution. When you listen closely, it becomes apparent that his holding up and robbing a British Army officer only to be betrayed by a faithless girlfriend is a metaphor for something else entirely. Folk-rockers Steeleye Span had a hit with All Around My Hat (I will wear the green willow). Not just a song about a girl remembering her distant boyfriend by wearing a sprig of willow in her hat, but subtly advertising other loyalties by wearing something growing and green. (And why is the boyfriend "far, far, away"? To get out of reach of the British...)
Marillion's track Forgotten Sons is a lament for Scottish soldiers killed in Northern Ireland, and a swipe at the politicians responsible for sending them there and the religious divide - also a big thing in Scotland - that sustains the terrorists.
Flogging Molly's song Drunken Lullabies is about The Troubles, and the hope that they may come to an end (may these shadows rise to walk again With lessons truly learned).