This week our blog features an extract from theatre practitioner and Digital Theatre Plus Study Guide writer Fin Kennedy's new book The Domino Effect and other plays for teenagers, published on 7 May by Nick Hern Books.

You can order your copy from the Nick Hern Books website at a 25% discount - use voucher code DTPDOMINO at www.nickhernbooks.co.uk/dominoeffect

I first experimented with writing for an ensemble in my very first play for teenagers, East End Tales, a series of dramatic poems about inner city life, written for multiple voices and inspired by articles in East London newspapers. At the time (2004) I was writer-on-attachment at Half Moon Young People's Theatre, developing my first professional play for young audiences for a national tour. That play, Locked In, involved only three actors, largely because they were all professionals who needed paying and also because the entire show had to fit into the back of a van. East End Tales, however, was the result of a short residency in an East London school, into which Half Moon sent me as part of my own professional development as I learned to write for their target age group.

Writing a play for young people themselves to perform, as opposed to professional actors performing for an audience of young people, is a very different thing. For a start, in the former, large casts are actively encouraged so that as many people as possible can take part. This presents challenges as well as opportunities. Maintaining coherent storylines and meaningful character arcs for ten, fifteen or even twenty named parts is not always possible, especially when the overall running time is unlikely to exceed 45 minutes. Then there is the nature of rehearsals stretching over weeks or even months, and the likelihood of cast changes due to teenagers' busy lives, clashes with other projects or just general drop-outs.

One technique I developed to deal with these variables is a choral writing style, which uses nameless narrators to introduce and guide the telling of the story. This can accommodate anything from two to twenty narrators in the chorus. Often the language is in a playful, lyrical style, which makes the lines easier to learn - the idea is that everyone learns the lot, so that in the event of cast changes (or drying on stage) others can cover the lines. This form also plays to one of teenagers' great strengths - acknowledging the audience and telling them a story directly. Young actors are naturally good at this, and audiences love its conspiratorial nature. Other, named, parts can and do emerge, but the chorus of narrators is never far away.

The three plays contained in this volume are therefore for large casts of young actors aged 13 to 19. Cast sizes can vary due to this ensemble style, but the minimum is about eight (for The Domino Effect, though it can be done with more) and the maximum about 16 (for The Dream Collector). Fast is more fixed as it uses named characters throughout, and tries to do justice to giving each of them a journey, but even so it can be performed with either 10 or 13 actors (depending on whether the four older parts double or are separated out). Ensemble casting can also include non-speaking parts, who can use physical theatre, dance and music to create stylised representations of the world of the play. In this respect, the only upper limit on cast size is the imagination of the company taking the play on.

Each script in this volume was developed with a different group of diverse young people in inner London, though the characters and stories are universal enough to suit most young peoples' groups. The specific circumstances of ethnicity, culture and geographical location are less important than a strong ensemble ethos. A willingness to experiment with a physical performance aesthetic will help significantly, as will a commitment to working together to create the onstage magic necessary to tell these stories in a way which will delight an audience, allow transitions to unfold smoothly, and communicate each story's emotional truth.

Each play was conceived under different circumstances and it may help those of you hoping to stage them subsequently if I tell you a little bit about how each of them came about.

The Dream Collector was the fifth play developed with my long-term collaborators Mulberry School for Girls in Shadwell, East London, with whom I have been creating new plays for over ten years. (Our first four are published by Nick Hern Books in The Urban Girl's Guide To Camping and other plays). However in 2012 we added a new twist. By this time our work had become known locally as a pioneering partnership between a playwright and an inner city state school. In an effort to continually evolve the way we work together, and to share some of the expertise we had built up, we decided to reach out to another local school during the making of our next play, and see if it was possible to develop a new play across two schools simultaneously. I approached local comprehensive, St Paul's Way Trust School in Bow, who were eager to be involved.

The practicalities of such an arrangement at first appeared to be problematic. If I was the sole writer then clearly I could only be in one school at a time. Yet running joint sessions, in which one school's students would travel after school to attend workshops at their partner school, would soon become expensive and logistically difficult. With sessions having to start some time after 3.30pm in order to allow the other school's students to arrive - what would the others do in the meantime?

After some deliberation, our solution was simple. As the one who was the most easily mobile, why didn't I travel between schools, taking the ideas for the play with me? In this way we hit upon what turned out to be quite a neat model. After-school workshops were held twice a week on different days, one in each school. I would develop ideas with Mulberry in one session, then take them with me to St Paul's Way, presenting them to their students, developing them further, then taking the new ideas back with me to Mulberry the following week. The whole thing became like a long-distance version of the party game Consequences. It was fun - each week the students were eager to see what new ideas the other school's group had added to their own. In this way, the two groups never actually met one another until the first draft read through.

All this had an impact on the play's form. The Dream Collector concerns a Year 11 school group who go on a Media Studies trip to an isolated country house which had belonged to an early black-and-white movie pioneer, Charles Somna. Upon arriving, they soon discover that Somna was responsible for much more than the creation of mere movies - as the inventor of the Somnagraph he had built the world's first machine for screening your dreams. Once they step through the movie screen and enter the Dreamworld, each of the young friends meets their dream double, the sinister Neverborn...

The idea of having essentially two casts within one play was deliberate. It was intended to allow two real casts to rehearse their parts up separately if necessary. While The Neverborn are present during the journey to Charles Somna's house, the Real World cast are not aware of them. In practice both casts could (in theory) rehearse their sections separately and come together later in the process to put the final show together. This could be useful in future iterations, if two groups within the same school cannot rehearse together for timetabling reasons.

However, once the play was written, it became clear that the logistics of joint rehearsals across two schools would be insurmountable. Who would direct the show? If it was to be two teachers, one in each school, how would creative responsibility be equitably shared? Would rehearsals have to wait each day for half the cast to show up from the other school? In which school would the set reside?

In the end each school agreed to stage their own separate production. At first this seemed to be a pity, but the benefits soon became clear. Each school had co-commissioned the play via an equal financial investment, and that investment suddenly reached twice as many students. Eventually, each school's students were able to visit one another's production and discuss the creative choices made with a deep knowledge of the play. For some, this became a piece of coursework.

In terms of the education and theatre sectors working together in future this got me thinking. If two or more schools co-commission a play from a writer, yet produce their own versions, suddenly the project becomes a lot more affordable. It multiplies its reach, and the writer gets two (or more) productions all in one go. In this age of austerity, this kind of innovative thinking could well come into its own. If any schools reading this are interested in forming consortia to work in this way to commission new work (and not just from me) then I would be happy to advise - do get in touch.

Fast was a very different process altogether. It was commissioned by a theatre company rather than a school. Y Touring has for 15 years been producing and touring plays for young people about complex science-based issues. Their unique 'Theatre of Debate' format allows young audiences to be involved in the creation of new plays right from the start, by inviting them, along with the playwrights who will be creating the work, to workshop days in which scientific specialists present different perspectives on the issue under discussion. I was invited to attend the debate day surrounding diet, fast food and food security, which took place as part of the development of Sarah Daniels' 2014 play Hungry. My brief was to conceive of an accompanying play for an ensemble of young actors along similar themes.

Fast concerns Cara, a 16 year-old student at a comprehensive in an unnamed small town, close to some countryside. Cara is from a farming family, and we learn that one year previously her father had taken his own life. When Cara's school holds a 24-hour fast in aid of Oxfam, Cara decides she will not eat again until Tesco and the other suppliers, whom she holds responsible for driving her father to suicide, are held to account. The play touches on issues of diet, commerce, class, industrial farming, the environment, grief, austerity and friendship with (I hope) wit and a lightness of touch. In Fast the ensemble are all named parts and as such have clear identities and character arcs, each with their own distinct view of Cara's actions. This allows for considerable ownership of each character by each cast member, and would lend the play to analysis and deconstruction, for example hot-seating each character to learn more about their background and views. Fast was workshopped at Regent High School in Camden before being performed by a young people's summer school cast in August 2014.

For The Domino Effect I returned once more to my long-time collaborators Mulberry School for Girls. In 2014, Mulberry was celebrating its 50th anniversary and was keen to take a new play to the Edinburgh Festival Fringe. Mulberry and I had built our reputations at Edinburgh, taking a play every year for three years between 2007 and 2009, with our third show, The Unravelling, scooping The Scotsman's prestigious Fringe First Award. (All three of our Edinburgh plays, plus one other, are contained in The Urban Girl's Guide To Camping and other plays).

The Domino Effect was conceived in summer 2013, while on a short break in France in which I watched again one of my favourite films, Jean-Pierre Jeunet's Amélie. Hang on, I thought. This is a Mulberry story. Set in the inner city, with a teenage girl at its heart, Amélie is about an introvert with an overactive imagination, which starts to spill out into the real world, until even she isn't sure what is and isn't real. I often met young women like this in Mulberry, and it seemed a good opportunity to develop a play looking at the interior worlds of these more introverted students (who are also not always the easiest students to engage in Drama). I started to wonder, what would an East London version of Amélie look like? As I knew Mulberry and its students so well, the school agreed for me to lead on writing a first draft then to workshop it with students afterwards.

Around the time I was sitting down to write the first draft, I was having some work done on my house. One morning one of the builders came up to my study and handed me a set of dusty Victorian dominoes he had found underneath our floorboards. Playwrights can be superstitious about these sorts of signs arriving as some sort of heaven-sent inspiration, and I am no exception. The metaphor seemed to be perfect - dominoes, and the domino effect, as a cascading symbol of actions we set loose into the world, knowingly or not, from apparently insignificant beginnings. All the subsequent sessions in school confirmed that this idea captured Mulberry's students' imaginations as much as it had captured mine. The resulting play about "small actions, big effects, and mastering the law of unintended consequences" ended up securing us our first five-star Edinburgh review and a clutch of enthusiastic notices comparing the dense, poetic text to Dylan Thomas's Under Milk Wood.

The Domino Effect was the first time Mulberry's Drama and Dance departments had collaborated on a show, and the script was conceived with this in mind. It is undoubtedly the most ambitious text I have ever written for a young people's group. The detail of the world it observes is not only about the audience seeing things through Amina's peculiarly observant eyes, it is about planting small references which will become significant later, and about charting the ripple of one's actions in an area of high density living. In performance it requires crystal-clear diction, an ensemble who support each other instinctively, and the sharpest of physical theatre aesthetics to bring the play's multiple locations to life in the blink of an eye. Every narrative section is intended to be animated onstage via the ensemble. The play will not work if everything stops for the narrative to be merely recited.

I have described The Domino Effect as a love letter to East London, and indeed to the wonderful Mulberry School, where I have spent a decade honing my craft. But I hope that the play will have a resonance far beyond the specific British-Bangladeshi community that inspired it. Ultimately, it is about showing young people that they have more power to change their own destinies than they could ever realise, whoever they are and wherever they are from. The play would suit mixed casts, though it also provides the opportunity for teachers to offer leading roles to Asian or Muslim students, and I would encourage them to do so.

Since writing these three plays I've been appointed Co-Artistic Director of touring theatre company Tamasha, a new chapter for both me and the company. In the immediate future it means I'll be doing less writing of my own and more working with other writers to develop a new generation of dramatists. But I carry the inclusive, community-focused ethos which inspired these plays with me into my new role. Having an infrastructure opens up some exciting possibilities - such as Schoolwrights, Tamasha's pioneering new playwrights-in-schools training scheme, the first of its kind in the UK. If you are inspired by the plays in this volume I'd encourage you to get in touch with us to see how we might be able to work with your school, to support and develop the work your Drama department is doing. As a national touring company, Tamasha has national reach, so it is not necessary for your school to be only in London or the south-east.

I could not finish an introduction to a collection of plays for young people in 2015, with a looming general election, without some reference to the current government's attempts to downgrade arts subjects, and especially Drama, in our nation's schools over the past five years. To be putting out a new volume of plays for schools at such a time feels positively defiant.

It is.

As I hope the plays in this volume show, and the many more by my colleagues still writing for young people, not to mention the Drama teachers up and down the country heroically defending their subject from a hostile government - to teach Drama is to teach life. It is to teach how to be human, how to have agency, how to be heard. How to work through our differences, how to compromise, struggle, think and feel. How to be an intelligent, successful and humane society.

I've written elsewhere that teaching creativity in schools is like installing the software on which all the other information will run. Disincentivising it within the curriculum makes no sense. To teach Drama, creativity, the arts, is to teach how to think for oneself, and ultimately therefore, how to become oneself. What lesson could be more important than that?

I hope that this volume, in its own small way, will help keep our subject alive in the place where its flame can burn most brightly - in the next generation's hearts and minds.

Fin Kennedy's new book The Domino Effect and other plays for teenagers is published on 7 May by Nick Hern Books.

Order your copy from the Nick Hern Books website at a 25% discount with voucher code DTPDOMINO at www.nickhernbooks.co.uk/dominoeffect