Jack Thorne: 'I’d do anything John Tiffany asked me to'

The Solid Life of Sugar Water, what's that all about then?

It’s about a couple who are in grief following a stillbirth. They are trying to reconnect after the child’s death. It’s basically following that journey, how they got together. I’m not very good at selling it, but it tries to be funny in places and it’s got a couple of incredible actors in it. They are fantastic.

Why did you decide to open at the Plymouth Theatre Royal before heading to Edinburgh?

Plymouth is an amazing place, they are an amazing supporter of new writing. They came in and partnered on the project and gave us some incredible notes and steers as we tried to make it work. Edinburgh seemed like the right place for it, I think people will get it more up there.

It's a far cry from your previous project (Let the Right One In) and your next one (Harry Potter and the Cursed Child)…

You never want to be in a box, you’re always looking to try and work stuff out. I’ve always tried to not do the same thing next. Graeae is a company I’ve loved being a part of and I’ve loved this process of putting this play together. There’s no rhyme or reason for why you do certain things in certain ways, but this has been a really lovely experience for me.

Did you have any personal experience of the subject matter?

My mum lost a child very late in the pregnancy, so that was in my head. But other than that it was lots of research. You don’t want to make a mistake with things like this. We tried to handle it with as much sensitivity as possible.

Did you have an idea of the casting before writing the play?

The great thing about Graeae is that they are an incredible company that is interested in making work with disabled artists, but they are very eager to wear the label of disability as lightly as possible. So when we were talking about this we decided we weren’t going to write it for a certain disability, rather we’d write it and cast it and see what effects the actor had on the role.

With Genevieve [Barr, who plays Alice] she was the person that most suited the role. She’s an extraordinary actress. We then started working out how to rewrite it for a deaf actor and what that did to their relationship, and actually it made their relationship a lot deeper. There’s a moment in the play when Phil [Arthur Hughes] still has not learnt how to sign because he’s so crap at it from the beginning and she’s so good at lip reading – which Genevieve actually is – and he improvises a sort of sign to Dire Straits' "Romeo and Juliet" and it’s kind of wonderful.

It’s that wonderful thing where something sort of sets you free, and casting Genevieve has set us free in a certain direction and I think it’s made it a lot stronger and wilder and I’ve really loved that.

What was the reaction like in Plymouth?

Really lovely actually. You always hope people will go with it and they did. The two of them on stage are electric and people really bought into that chemistry. The work that Amit [Sharma, director] has done on the script – I really like directors who push it a bit and say ‘actually I think it should be like this’, John Tiffany is amazing at that and Amit is also incredible at it – he’s made the piece a lot better than it deserves to be. It’s been really amazing.

I have to ask about your next project, Harry Potter and the Cursed Child, is there anything you can tell us about that?

I’m not allowed to say anything. There are PR people with poison darts waiting to destroy me [if I say anything]. The only thing to say is that it’s incredibly exciting. It’s been a brilliant journey so far and working with Jo, she’s an incredible woman. I’d do anything John Tiffany asked me to do, but when he asked me to do this, that was an amazing moment.

The Solid Life of Sugar Water runs at the Queen Dome – Pleasance Dome, Edinburgh at 4pm from 5 – 30 August 2015.