At Craiglockhart War Hospital near Edinburgh in 1917, as World War One boomed across the Channel, Siegfried Sassoon and Wilfred Owen met for the first time.

Both were being treated for ‘war neurosis’. Owen was suffering from post-traumatic stress disorder after a particularly horrendous trench mortar explosion that left him lying injured for days among the remains of a fellow officer. Sassoon, a lieutenant and recipient of the Military Cross for bravery, had become completely disillusioned by the futility of the war and the many thousands of lives lost. He had written a letter that was read out in the House of Lords, stating that he believed the war had become an aggressive conquest and no longer had a just cause and, therefore, he refused to fight. The letter was also sent to the press and so had become very embarrassing to the military and to the country’s war effort. Instead of instant dismissal or a court martial, they sent him to Craiglockhart.

The two men only spent a few months together, but the impact they had on each other was profound, and Blackeyed Theatre’s revival of Stephen MacDonald’s moving 1980s play Not About Heroes, currently touring the UK, chronicles the unique and deepening friendship that developed between the two soldier poets from that first meeting in 1917 to their final meeting in August 1918, shortly before Owen’s return to active duty and his tragic death, just a week before the war ended.

“The two of them met in this hospital quite by chance,” explains actor James Howard, who plays Sassoon. “They were from completely different backgrounds – Owen was middle class while Sassoon was from a much higher class, monied society, so they probably wouldn’t have met.

“The play starts with Sassoon quite haughty, almost like a teacher to Owen and not really seeing the full potential that Owen is showing. Gradually, as the play develops, we see that relationship softening and they really become equals quite early on, with Owen arguably overtaking Sassoon as the greater poet – Sassoon helped create the poet that Owen became.”

The play is told through the eyes of the older Sassoon, who is looking back on events 14 years later, and interweaves extracts from the men’s real diaries, letters and poems, and it suggests that, as James says, their intense friendship was the key to unlocking Owen’s genius as a poet and liberating him as a man.

But this came at a great cost to both.

“Sassoon is looking back from the 1930s and is guilt-ridden,” explains James, 38. “He survived the war and Owen was killed. He’s quite a tortured man – he feels that he may have been responsible for Owen going back out and being killed. Owen felt like, to become the great poet that he thought Sassoon already was, he needed to experience the front line, to experience the real horrors of the war.

“It’s not just a historic piece,” continues James, who stars alongside Ben Ashton as Wilfred Owen, “because we’re forever at war, there are soldiers on the front line every day risking their lives. It’s about the futility of war in all sorts of times and places. It’s a very moving piece.”

  • Not About Heroes is at Harrow Arts Centre, Uxbridge Road, Hatch End, on Friday, November 28 at 7.30pm. Details: 020 8416 8989, harrowarts.com