Go wandering around a bookstore or a cinema and you’ll struggle to go five minutes without seeing a film or novel that boasts the tag line “Based on a true life story! Telling stories based on real life can add a whole new level of excitement, interest or inspiration for the audience. It can also add a new level of empathy and intimacy to a story, since you know its characters did actually once exist (or even still do) and lead to the sharing of some absolutely incredible stories – think Schindler’s List, The Pianist or A Beautiful Mind to name but a few.

Certainly, since the start of this century, film and books based around true stories have risen drastically in popularity. With true stories being as remarkable and compelling as anything fictional could be, real-life stories are a resounding success in both films and novels. But is this also the case for theatre?

At first glance it doesn’t seem to be. Plays seem to be as fictional, varied and imaginative as ever they were. Let’s start by taking a selection of the successful shows that are currently showing in London (and beyond) and see how many draw on real life, and how many are pure invention. To start with, there’s the constant flood of dramas: the National Theatre is showing a selection including the emotionally striking Sea Wall and a new version of the high-spirited Liolá. Then there’s the staple diet of musicals, with classics such as Les Miserables fleshing out the scene alongside contemporary pieces like Tori Amos’s latest project The Light Princess… all apparently very fictional. Even to the extreme of performances along the lines of Punchdrunk’s The Drowned Man: A Hollywood Fable, a fantastical tale in a derelict setting and about as un-real as theatre can get. Fiction and storytelling seem to be the heart of theatre as we know it.

Take a closer look though, and it becomes clear that there are in fact many theatre shows around that actually are based on true stories. In fact, theatre has often been used as a genre to take on real life, up-to-date, current affairs, be they political, ethical or simply good food for theatre. There’s a growing trend in using plays based around real life events to champion an opinion or draw attention to an issue. Everything from arms trading to Iraq has been translated into theatre. Even the recent media phone-hacking scandal is inspiring its own play by Richard Bean.

Then, as well as plays based on a single event, there’s the rarer but still present sprinkling of memoir and biography in theatre. This can be seen emerging in works like Cush Jumbo’s Josephine and I – a play based both on the life and fame of 1920s film diva Josephine Baker as well as Jumbo’s own experiences. Similarly, Matt Charman’s The Machine (shown as part of the Manchester International Festival) is based on the famous chess match between Soviet chess master Garry Kasparov and super-computer Deep Blue. But even these plays, based utterly on reality, will undoubtedly include more than a few degrees of fictionalisation.

On the other hand, there’s the question of whether or not, for a play to be classed as ‘based on true events’, it necessary needs to be an accurate retelling of those events. A good example here is the upcoming drama Solomon and Marion, starring Janet Suzman and inspired by the death of one of her fellow actors and friends in South Africa. The play’s plot is fictional – as are its characters – but at the heart of the story is a true event. Where does a play like this fit into the scale of fact and fiction? And does this mean that for a play to be successful, it must be at least somewhat fictional?

If you ask me, what defines fact and fiction in theatre is how easily the two can blur together. I think it’s fair to say that any playwright would struggle to write a script that had absolutely no influence from the world around them. Maybe it’s because the nature of being on a live stage means that already life cannot be represented completely accurately – but theatre has the ability to take, from a real event or story, a single action or idea to build a whole new story around. The new story can be just as credible and honest as the true version of events. Fact and fiction can both make successful and poignant theatre, so when it comes down to it, it doesn’t really matter whether a story is true or not, it just matters how well it’s told.