Emma Jane Unsworth wrote Animals and also penned the screenplay for the film, which is currently on release. She tells John Byrne about the process and the task of switching the story from Manchester to Dublin.

Starring Alia Shawkat (Arrested Development, Search Party) and Holliday Grainger (The Borgias, Great Expectations), Animals follows best boozing buddies Laura and Tyler. It's been described as female Withnail & I which is certainly a compliment.

Laura's a struggling writer working as a barista, while flatmate Tyler is an American estranged from her family, and not short of a few quid. In their late twenties, they consume industrial levels of wine and drugs.

The dynamic of their relationship is altered when Laura meets and falls for Jim, who's a teetotaller.

Right. Scene set, so let's get to this chinwag with the creator of Animals, Emma Jane Unsworth.

John Byrne: Obviously you wrote the book as well as the screenplay. Did you have a film in mind when you were writing the novel, and how did you find the experience of going from one to the other?

Emma Jane Unsworth: I think I'm quite a visual writer anyway, I think quite often with scenes in mind and with the way that it looks more than anything - more than any of the other stuff like what techniques and devices for a writer.

I always was hoping as well that I'd get asked to do the screenplay. Because I've always wanted to and then the producer who optioned it she said do you want to write it? I was like 'yes!' It's a novelist's worst nightmare to do it. I've got friends who just would not touch it, wouldn't want to do it. But I wanted to do it. I really did.

So it was great to have that chance, and the best thing about it was that it was so different to novel writing in that it was just a massive collaboration. You've just got like lots and lots of people working on it. It's like being on a tour bus.

Jesse Armstrong  is this really famous screenwriter who said that the difference between writing a novel and writing a screenplay is that writing a novel is like trekking the Arctic on your own - you can't look up, your heads down. The weather is terrible, you don't know if you're gonna die or go mad or both.

Then if you're writing the screenplay, it's like you're all on the bus together, going on this journey.

And that is what that felt like, you know that and there's pros and cons to both the pros being at least when you're on your own it's completely yours. You're making every single decision - but that can be quite lonely too. And you don't always know whether you do the right thing, where at least if you've got more people's input than you've got a bit more of a chance, perhaps.

Both Laura and Tyler are hitting their thirties. Do you feel that there's still that huge pressure thing when you reach that age? Marriage? Kids? Mortgage? All of that.

Yeah, I felt it strongly, but I wrote the book a long time ago now. I wrote this book in like, 2012. So it's a while ago, and I hope things have changed and hope things are changing, but I daresay they've not changed that much.

And I think that there are these pressures still, you know, to be and do certain things and for women especially, you know, at a certain age to have to do certain things if you're doing. There's a biological clock and there's no getting around that. So yeah, I think that's still a very real issue.

Okay, the book is set in Manchester. The film is set in Dublin. Obviously because Dublin's a much better place than Manchester?

Well, it for financial reasons. And it felt huge, like a huge move. I don't really know Dublin. I've been like once or twice. But, there are actually a lot of similarities between the two cities.

So the Northern Quarter [something like Dublin's Temple Bar] was where a lot of the book was set. There are all these nooks and crannies where you can have all sorts of adventures.

And getting to know Dublin well, there are all these nooks and crannies where you can have nocturnal adventures as well. And so it really felt as though it was a sidestep without compromising too much. And the director had a choice where she could shoot it in Dublin and make it look like Manchester.

But to her credit she said: 'Nah, it would be a waste of Dublin' - and she's Australian. So she said she wanted to celebrate the city and use the city. And if we're going to do it in Dublin, we're going to do it as Dublin. And so we did.

We were worried about Holliday doing the Dublin accent, because she's from Manchester. We had to ask her if she's going to be up for this, but she was.

Holliday Grainger and Alia Shawkat's onscreen chemistry as two BFFs is very believable. You must have been thrilled to get them on board. What was it like working with them?

It was amazing from the start! I'm not just saying that. Holliday was attached first and as soon as I saw here I was like, brilliant. Ginger, Mancunian, perfect. And she really loved projects and she stuck with it through all the undulations that a film being developed and financed goes through.

And then Alia – as soon as I saw her, I felt she looked like a Tyler. It's not that important, but she looks like Tyler as described in the book.

The chemistry was so key to the story; the key to the whole vibe of the film. It's like, if they don't get on, we're screwed! But they did. And the director gave them all these little tasks to do around Dublin together, some of which involve drinking, and some of which didn't.

And they got to know each other and just got that right. Part of it was natural, they really wanted to work together, which was great. They were excited, which meant that we were excited because we knew that would translate well, but then they're professionals as well. They knew what they needed to do, to give to those parts and that relationship what was needed.

The film was shot during the Repeal the Eighth referendum here. For a movie about two strong, independent women who refuse to be judged, this must have added to the vibe on set?

Once we knew the film was being based in Dublin we had to change parts of the script that were about pregnancy and stuff because obviously that would be massively different. The bit where

Laura's sister Jean says she's pregnant. If Laura thought her sister might not want that, it would be a huge tragedy and a huge problem.

So we had to tweak the script to show that. And while Repeal the Eighth was going on, there was a march. And then Tyler's got a Repeal the Eighth sweatshirt on at one point in the film. So it felt like that actually intensified having it in Dublin because, obviously, so many of the themes are about women's bodies and ownership of their bodies. So Dublin felt like the right setting for this story of these women too.

Animals is currently on general release and here's Laura Delaney's review.