Novelist Michael Morpurgo already thought the folks at the National Theatre were mad when, in the mid-2000s, they asked to adapt his 1982 novel War Horse into a play.
So, it's perhaps not surprising that in 2007, when War Horse opened at the Olivier Theatre on London's South Bank, Morpurgo sat in the audience for its first preview performance and rather than feeling delighted, tried to puzzle out why it wasn't working.
"Everything like the puppets, the music and the design was wonderful but it just didn't work," he admits. "It was too long and all over the place, and probably needed another month of rehearsals…"
He thought the National theatre team might be tempted to throw up their hands and walk away from it but instead, meetings with cast and crew followed, the production was cut right back and it was "knocked into shape".
So when Morpurgo returned to the theatre later that month, on press night – the first night proper – he could feel the audience becoming engrossed and then emotional.
"… I knew straight away that something extraordinary was happening because all of these critics and theatrical stars were in buckets of tears."
War Horse is now the National Theatre's most successful production to date, transferring to London's West End in 2009 and running until 2016. Adapted into a feature film by Steven Spielberg in 2001, it also enjoyed two years on Broadway and has been performed in countries such as China, Canada and even Germany.
"In Berlin, it had a German cast playing this Devon-based British story about the First World War and was staged in the same theatre in which the Kaiser would have sat in at the time of the First World War," says Morpurgo, 75. "What's remarkable about it is that while it's called War Horse, it's actually a play about reconciliation and how important peace is to all of us wherever we live in the world because one of the things about this horse is that it changes sides, so we see the war from all sides."
He believes the War Horse we will see in Auckland later this month is far superior to the show that first premiered in London in 2007.
"The National Theatre has never given up trimming it, making it a little sharper here or changing a bit there," he says. "They're always improving it, so by the time it gets to New Zealand, it will have had twelve years or rehearsals. It's now a much better show by miles than it ever was on that first night, and that's been wonderful to witness."
And also unexpected.
Centred round a young soldier called Albert who goes off to in France to track down his beloved horse Joey, the idea for War Horse came to Morpurgo after he met several veterans in his local village of Iddesleigh in Devon. They told him about working with horses during World War I.
"It's very much a story of the place where I live, as it draws on the history of the men who went from that particular village to that war. In a sense, it's a very narrow story, but what I didn't realise was that it would eventually have universal appeal, although I have to say that it wasn't the book that did that, it was the play."
Indeed War Horse was far from an instant hit when it was published in 1982. It nearly won the Whitbread Prize in 1982; it was translated into one or two languages but it never galloped up the best seller lists or garnered much buzz. That said, it stayed on his backlist and has never been out of print.
"It just was never a popular book."
Morpurgo's luck changed after the mother of National Theatre director Tom Morris bought a copy of War Horse after the author talked about it on the radio. Morris wanted a project where he could use the astonishing puppeteers from South Africa's Handspring Theatre, who are responsible for creating Joey the horse and the other creatures in the play.
"He really liked what they did and wanted to do something with their work on a big stage, where the puppets are not just part of the production but the stars of the show," recalls Morpurgo.
"He'd been looking around for some time for the right story – something with an animal at the heart of it. His mother rang him up and said 'I've just read this book which has a horse as the main hero, which is extraordinary because your grandfather went to the First World War with horses,' which Tom didn't actually know."
With fellow director Marianne Elliott, the National's then-director Nicholas Hytner and numerous musicians and designers, Morris spent two years meticulously developing War Horse, involving Morpurgo at every step.
"They've been really good to me as I've been there right from the very start, sitting around a table when we saw the first mock-ups of the horses," he says. "All the way through, I've been part of the process, commenting on scripts and going to rehearsals. I was really just a bystander, an onlooker, but I've witnessed the evolution of a small idea into a phenomenal theatrical performance, and to be just a small part of that has obviously changed my life."
What: War Horse
When & where: The Civic, from Friday, June 21 – Sunday, July 14