Rescued from hell: the war veterans who took to the stage

I write this from seat D8 in the circle of the Theatre Royal, Haymarket. On the stage below, a group of physically and psychologically wounded servicemen and women – all but one of them still serving – are rehearsing a scene from The Two Worlds of Charlie F, a play I've written that follows the fortunes of Corporal Charles Fowler and other soldiers from the moment of their wounding right through to their recoveries back in Britain.
Though Charlie F happens to be fictional, the cast have lived through its story. Earlier this morning, a member of the group was taken to hospital: the intensity of his pain had made him vomit outside the stage door of this London venue. Nearly all the soldiers are on medication, and the scene they're rehearsing is about this very subject – about not being able to sleep because of pain, medication and flashbacks, having been wounded in Iraq or Afghanistan. "Worse, always worse at night," they sing. "I'm scared, scared to put my head on the pillow."

British drama hasn't shirked its duty when it comes to depicting the realities of war, and recent plays such as National Theatre of Scotland's Black Watch and Andrew Motion's Incoming have drawn upon conversations with service personnel and their families. But when Alice Driver, a producer for the theatre's in-house charity, Masterclass, first approached me about the project, what most excited me was her ambition to use soldiers and marines not only as source material, but also as actors. Working with the MoD and the Royal British Legion, we advertised for volunteers. No one was turned away.

For a month, director Stephen Rayne and I travelled the UK. We became well-acquainted with the names of certain drugs, types of prosthetics, military jargon. We visited barracks, PRUs (Personnel Recovery Units) and rehabilitation centres. The statistics were shocking. In Afghanistan, 22% of combatants have been injured – a higher percentage than during the second world war.

Charlie F aims to offer a troops'-eye view, and it's been important that I shed any personal views on the last 11 years of conflict. We didn't want to create a political play, but a theatrical rendering of what these men, women and their families have been through.

We began rehearsals just a few weeks ago. Working alongside five professional actors, who play ensemble parts, they've gone from being soldiers to performers in very little time. And as well as the usual theatrical obstacles, there have been unique challenges: tiredness and memory loss; the angle of the stage makes walking with prosthetic legs tricky; squaddies enjoying London a little too much (one went briefly awol; another turned up with a broken jaw from a fight).

The benefits, however, have vastly outweighed the difficulties. As well as having access to a remarkable range of material through their stories, I've been able to write for them specifically – weighting scenes towards someone's singing talent, another person's comic timing. The result hasn't produced verbatim theatre in the purest sense, but rather in terms of perspective and tone. That's also true of their performances. There is a quiet power to their delivery, fuelled by the desire to shed light on a subject that deserves to be closer to the centre of public conversation. During rehearsals, a young veteran known to two of the cast took his own life (he'd been suffering from severe post-traumatic stress). It was a reminder to all of us of why we're performing this play.

Not that Charlie F is about hopelessness. From the moment the company came on board, they imbued it with hope. At one point in the script I reference a line of poetry by the soldier poet Alun Lewis, written in 1943 from his hospital bed in India to his wife in Wales. It captures what so many of those on stage are discovering, or moving towards. "Love," Lewis writes, "survives the venom of the snake."