100 years on, the Battle of the Somme continues to haunt the pages of Irish history. One of the First World War's bloodiest battles, it claimed the lives of more than 420,000 British and Irish soldiers. Just as the 1916 Easter Rising was a historic juncture in the formation of Irish Republican politics, so the Battle of the Somme was pivotal in the entrenchment of Ulster Loyalism. Wedged between Republicanism and Unionism, this mighty play of needless bloodshed, memory and love unites the two great narratives from that momentous year.

How appropriate that the Abbey Theatre concludes its centenary celebrations with this play, bringing the human sacrifice of eight young Ulster men to life with a violent, reflective vengeance.

The foreboding tone is instantly set by Ciaran Bagnall’s murky Beckettian inspired sets, infusing the audience with the claustrophobia of trench life. Paul Keogan’s blood red backdrops and dramatic lighting depict the red sky of Ulster and the inevitable carnage that takes place under it.

But it is our protagonist war-veteran and sole-survivor Kenneth Pyper (played by Sean McGinley) who gives us a fascinating window into the wartime psychosis that will befall our characters. Pyper is your typical First World War survivor, riddled with PTSD, survivor’s guilt and a memory of war so palpable that he might as well have died alongside his comrades in 1916.

As the rest of the cast assemble, the audience is staggered by the depth of their characterisations. There is the handsome and discreetly gay Craig (Pyper’s lover), the endearing Millen and Moore bickering like an old couple, the faith-stricken Roulston and the cynical Crawford; and last but not least, the brash but lovable Belfast bullies Anderson and McIlwaine, both haunted by memories of the Titanic. This wonderful cocktail of characters represents conflicting aspects of Ulster society. The terror of the trenches sees them overcome their differences to form an unbreakable unit that would – and does – die for each other.

Over two engrossing hours, the audience watch in uncomfortable silence as the characters they grow to love march towards their inevitable deaths. True, not all is doom and gloom, and the play is infused with nuggets of comedy gold. There are humorous turf wars, accent bashing, rampant sectarianism and insults against Fenianism.

But despite this boyish camaraderie, and the boasts of dying for king and country, the looming sense of dread never vanishes. It grows stronger as the audience cannot shake the knowledge that there will be no happy endings here – these boys' generation is marked for death.

We watch helplessly as they go from childish idealism to disillusioned fatalism. “We are the sacrifice” realises the horrified McIlwaine. “We are all going to die for nothing… Belfast is going to die.”

As the curtain drops you find yourself assuming the role of the bewildered Pyper, as you ask yourself the unanswerable question – what was it all for?

Observe The Sons of Ulster Marching Towards the Somme is on at The Abbey Theatre until September 24