‘I don’t think anything is impossible to put on stage': Sally Cookson on the enormous challenge of adapting A Monster Calls

Patrick Ness's bestselling novel is about a grieving boy and a giant, demonic tree. How on earth do you bring it to life in the theatre?

Matthew Tennyson plays 13-year-old protagonist Conor O’Malley, who is buckling under the strain of his mother’s cancer (Photos Manuel Harlan)

“I don’t think anything is impossible to put on stage,” declares director Sally Cookson. You only need to look at her new project to see how sincerely she believes this.

Patrick Ness’s 2011 novel A Monster Calls is one of the most brilliant and harrowing children’s fantasy books of recent times. It is a sandpaper raw study in grief, given further poignancy by the fact that it was conceived by the writer Siobhan O’Dowd while she herself was dying of cancer, and passed on to Ness to write after her death.

In it, we meet 13-year-old protagonist Conor O’Malley, who is buckling under the strain of his mother’s cancer: the endless treatments, the refusal of adults to be honest about her prospects, the embarrassment and the guilt at the special allowances everyone makes for him.

But then, one night, at 12.07am, the ancient yew tree outside his house “comes walknoring”. It reveals itself to be a terrible living thing, possessed of a ferocious appetite for destruction.

Director Sally Cookson in rehearsals, whose career has taken off in the last few years with hits such as Peter Pan and Jane Eyre (Manuel Harlan)

But it also wants to tell Conor a series of unsettling fairy tales about the moral greyness of the world, and ultimately becomes a sort of demonic father figure – a world away from his own, feckless dad, who divorced Conor’s mother and moved to America while Conor was little.

A Monster Calls has already been made into a critically acclaimed 2016 film, with Liam Neeson offering his best performance in aeons as the voice of the behemoth. Which was, of course, computer generated – after all, how the hell would you portray this thing on the stage?

This was not something that unduly bothered Cookson – a small, sharp, impassioned woman, whose lengthy career has really taken off in the last few years with her hits Hetty Feather, Peter Pan and Jane Eyre.

Ness’s novel had been on her list of potential adaptations for years: she literally used to carry a copy around in her bag with her.

“One of the Hetty Feather actors said to me that I needed to read it,” she says. “So I did, all in one sitting, as many people have done, and I just thought it was the most brilliant, important story. It packs such a massive emotional punch, and the combination of gritty realism and magic really appealed to me.”

She didn’t expect to be able to make it any time soon, though (“I knew that somebody else had the rights, I heard maybe it was the National Theatre”). But then, one day, Old Vic artistic director Matthew Warchus invited her in to discuss her working with them. He showed her a list of projects they had the rights to, and at the top was A Monster Calls.

A Monster Calls has already been made into a critically acclaimed 2016 film, with Liam Neeson as the voice of the behemoth (Manuel Harlan)

“I took the book out of my bag and said ‘yes please’.”

This immediately saddled Cookson with a (literally) enormous problem: how to make a monster.

“I was adamant that I didn’t want a set piece tree that was trundled on, trundled off, and I didn’t want a massive puppet,” she says. “And it was very important to me that an actor represents the spirit of the tree, because early on I’d had a conversation with Patrick who said to me that he was happy for me to do this however I wanted to do it, but he just wanted me to remember that it’s really important that the tree is a male father figure.”

The problem was that she had yet to come up with any idea for how to represent a gigantic, raging, otherworldly, arboreal monstrosity that could appear to Conor in the blink of an eye.

Where other directors might have hunkered down in a bunker with their designer for a few months, Cookson took a different approach. She has long devised much of her work with her actors, and so she gathered together a selection of performers along with her designer Michael Vale and a few other creatives, and spent a week playing with ideas.

The monster is portrayed by actors clutching large bits of rope, wound together to form the tree (Manuel Harlan)

After several dead ends, including a large amount of time spent building beautiful but fundamentally useless monsters out of chairs, they found some coils of rope in the rehearsal space. Suddenly, something clicked into place.

“As soon as we saw these hanging ropes, we wound them up and they became a tree instantly: we found our monster.”

It may still sound somewhat improbable that a few actors clutching large bits of string could compete with the book’s merciless sparseness, or with the expansive computer generated visions of the film (which Cookson studiously avoided watching during the creative process, though she’s since enjoyed).

But prior to its main summer run at the Old Vic, A Monster Calls has in fact already had an opening, at a different Old Vic – the one in her hometown of Bristol, currently run by War Horse director Tom Morris. Cookson is adamant that her work be seen regionally, and the Bristol run was conditional to the production as a whole.

Selina Cadell (left) plays the grandmother of the young boy struggling to deal with grief (Manuel Harlan)

Though national press are yet to be invited, local and social media response was universally rapturous, and Cookson is briefly overcome with emotion when I ask her how it went: “It was absolutely mind-blowingly brilliant.”

In the final analysis, we‘ll know it’s really worked if it moves us to tears. The monster is the great talking point, and the big technical challenge, but it’s all for nought if Conor’s story doesn’t hit home with the same devastating impact as in Ness’s novel.

It’s a story about a fantasy, but it’s also one about reality, specifically the reality of grief. The two must balance or it’ll come apart – and no amount of rope will hold it together.

“You have to try and include both things if you want to serve and honour the story and I am not frightened of going to that harrowing place,” says Cookson. “As a society, we’re reluctant to expose anyone to difficult emotions, we try and protect not just our children but ourselves as adults. We don’t like to see people upset. But it’s part of who we are and until we deal with it we’re never going to be stable adults.”

Face the monster, if you’re brave enough to dare – but don’t forget to arm yourself with a hankie.

‘A Monster Calls’ is at the Old Vic in London, 7 July to 25 August