Oh, we were getting along famously, his novel War Horse and me, as the 17:30 pulled out of Euston. Cantering through the countryside as the train zipped beyond Warrington Bank Quay, all was right with the world.
Clouds gathered near Preston as the guns of the First World War boomed. As Carlisle approached we were in the trenches and a lump the size of Jupiter had lodged in my throat. When Glasgow eventually appeared, it did so through a peasouper of tears. Happy times.
It is one of the wonders of Morpurgo that while not every one of his 100-plus books prompts such a reaction, the former children's laureate has often made a lot of people very happy by first making them rather sad. "Emotionally involving" is the term Glasgow's Julie Bertagna, author of the Exodus trilogy, prefers to use when describing the Morpurgo style. Lindsey Fraser, a literary agent with Fraser Ross Associates, and a former director of the Scottish Book Trust and of the children's programme at the Edinburgh International Book Festival, says, "He is shameless about manipulating your emotions. Whenever I read a new Michael Morpurgo I am reminded of what I was like when I was 11."
Expect similar reactions when Private Peaceful, the latest Morpurgo tale to be adapted for the cinema after War Horse, opens next month. Starring Richard Griffiths, Jack O'Connell and Maxine Peake, this best-of-British story of two farm lads who go off to war is stirring, inspired, action-packed and, yes, more heartbreaking than the newly orphaned Bambi making a guest appearance on a Lassie Christmas Special. Given the often poignant nature of his award-winning books, it comes as something of a relief to find Morpurgo positively chipper. "There is always time for The Glasgow Herald," he says from his home in Devon. "You've always been a very kind newspaper to me. There are some newspapers who followed your career when it wasn't anything very much and gave you a bit of a lift when no-one else was paying any attention."
Other than his good manners and his love of the countryside, there is not much about Morpurgo that is simple. As shown in our conversation, and in War Child To War Horse, a new biography by Maggie Fergusson, Morpurgo is a hard butterfly to pin down. He may be a children's author, but getting a sense of him beyond his books is far from child's play.
Private Peaceful is Morpurgo's fourth novel to be turned into a feature film. Made by director Pat O'Connor in a plain fashion to suit the film's budget and the book's style, it is a very different animal to Spielberg's epic, £40 million War Horse. (The stage show of War Horse is coming to Scotland next year.)
As with War Horse, Morpurgo was deeply moved by Private Peaceful. "Both films made me cry but then I don't think I'm the best person to judge, because I am very moved by those stories still. The great test is if no-one knows the story and they are seeing it for the first time."
Private Peaceful is perhaps the most intense book he has written. "Probably because the subject matter demanded the best of me as a writer. It's not a subject you can play around with."
Indeed. The book had its roots, as so many of Morpurgo's tales do, in reality. (His new book, A Medal For Leroy, stems from the true story of a black officer who served in the British Army in the First World War.) He was visiting the In Flanders Fields museum in Ypres, Belgium, when he saw a telegram informing a mother that her son had been shot at dawn for cowardice. "I felt as if a knife had gone into my heart," says Morpurgo.
He made further inquiries and discovered that from 1914-18, 306 soldiers on the British side had been executed for offences ranging from falling asleep on duty to desertion. Many were suffering from shell shock. Only the French Army, with 600 executions, shot more. The Germans executed 48.
Morpurgo joined the campaign to have the British troops pardoned, writing, among others, to Cherie Blair, wife of the then Prime Minister. "She wrote a very sympathetic letter back and passed it on to the powers that be in the Ministry of Defence." In August 2006, the Government announced that there would be a group pardon.
It was an ideal campaign for Morpurgo, a clear case of a wrong that had to be righted, and it would not be the last he would fight. It also involved a subject, war, that is as much a part of him as the head on his shoulders. Though his two most famous books, War Horse and Private Peaceful, are set in the First World War, Morpurgo was born much later, in 1943, in Hertfordshire. His uncle, Pieter, who was in the RAF, was killed in 1941. The death devastated Morpurgo's mother. As a child growing up in London, he played among the bomb-damaged ruins with his older brother.
He can remember the years from five to nine with "enormous clarity". I ask him to take me on a tour of what his younger self sees and smells. We are back on a London street. He is crawling through the basement of his house into a bomb site. There is a whiff of fires, one of which will eventually spread to his own house. Then he is scuffling through leaves, the odour of smog thick in the air. Over there is the horse that pulls the milk cart: sweat and oats and warmth.
Reality back then was weird but wonderful. Perhaps that is why he has never been fond of fantasy fiction. "I have a problem reading JK Rowling and Philip Pullman, both of whom are completely wonderful writers," he explains. "I've read them, but getting into them is enormously difficult for me. It's my fault."
Morpurgo, Rowling, of Harry Potter fame, Pullman (His Dark Materials) and Dame Jacqueline Wilson (Tracy Beaker's creator) are among the writers most often credited with elevating children's literature to its current, highly regarded, financially lucrative position. One of Morpurgo's unique selling points, to use the business-speak, is that his stories can be read aloud to older children as well as younger ones. While parents may feel the odd twinge of distress at where the stories go, Morpurgo's younger fans have no such hang-ups about venturing into difficult terrain.
Lindsey Fraser can understand that. Take Private Peaceful, she says. "It's about war. It's on the news every night. No child doesn't know in rough terms what war is about. He is not irresponsible in what he gives children to handle because he writes it in such a way that they are very, very well cared for as they read through some quite painful scenes. He's a man of great humanity. I know that sounds a bit pompous, but it is so brilliant to see him at this stage in his career having achieved as much as he has. The potential was always there, but there could have been times where it just didn't happen for him."
Those times. Morpurgo turns 69 this year. War Horse wasn't published until he was 39. By then he had married, attended but left Sandhurst, graduated from university (English and French), become a husband, a father (he was 21 when his first son was born) and a teacher. He had also started, with his wife Clare, Farms For City Children. The idea was to give children from poor backgrounds a working holiday on a farm. Morpurgo and Clare, whose father was Allen Lane, the Penguin Books founder, were well off by this stage and could afford to embark on such an ambitious adventure. Still, it cost them a lot, in hard work and determination as well as cash. As is clear from Fergusson's biography, it also cost them time with their own three children.
More than 50,000 children have now taken part in the farms project. Morpurgo is in no doubt about its value. "It is rather like a great book. To give a child an opportunity to have a deeply unforgettable, enriching experience, whether it be through a book or a week on a farm, can be life-changing. The whole thing about educational experience is that it has to be, should be, life-changing, particularly for those children who need a life change more than most."
At the Edinburgh International Book Festival last month, Morpurgo spoke of his determination to open a farm in Scotland to go with the existing three, in Devon, Wales and Gloucestershire. "If any of you have this uncle," he appealed to his audience, "who has an estate in Aberdeenshire of 1000 acres and simply doesn't know what to do with it and has a great mansion, could you please let me know?"
Someone who has attended Morpurgo's readings with her children speaks of the rapt, cathedral-like silence in which he is heard. This is Morpurgo as a benign Pied Piper, able to beguile children and adults alike. He takes what might be termed a Jesuit approach to children's development, believing that early nurture pays enormous dividends. Children in Britain don't get a good deal by and large, he believes.
"In Scandinavian countries they have worked out that investing in the happiness of children early on is critical. Here, the education system is organised backwards, with all the effort, money and prestige afforded to university education and not much attention paid to the early years. Even when it is, not all children benefit.
"Yes, for those kids who have homes where people talk, travel, read books, the education they get at school is pretty good. It is, if you like, seed thrown on fertile soil. But we have millions of children who are not in that category, and our problem is engaging with those children."
He considers his own childhood generally happy, which comes as rather a surprise having read Fergusson's book. Morpurgo's mother remarried when her sons were young (his name comes from his stepfather). By all accounts his stepfather, a book editor, a publisher and later a professor, was a domineering man, and young Morpurgo missed his original dad, the actor Tony Bridge, enormously (the two were eventually, and joyously, reunited).
"I think all the adults around me did their best," he says, adding that his stepfather could be "a little impatient from time to time". But no, he concludes, he has nothing to grumble about. "A lot to thank them for, actually."
Morpurgo's two sons – he also has a daughter – did not contribute to Fergusson's biography, in which she writes: "One cannot understand Michael without knowing that his relationship with them has been troubled and that this is a source of bitter regret and, he says, 'regret lasts longer than any kind of pleasure that comes from success'."
Fergusson steps delicately around the possible reasons for this, ranging from Morpurgo's run-at-life personality, to the time eaten up by the farms project. The book was a joint effort, with Morpurgo contributing seven stories to go alongside the factual chapters.
I don't get much further when I ask Morpurgo if he was close to his own children when they were growing up. "I was close and I am close," he says, "but it's more complex when you are a young father, which I was. It is complex, it is sensitive, it is also private."
Get Morpurgo on to the subject of his six grandchildren, however, and he positively fizzes. In speaking about his relationship with them, and later, when he talks about his own personality, one can speculate a little more about why his relationship with his sons might have been troubled.
At 69, says Morpurgo, he has now "grown into my own skin" and is more relaxed. Relationships with grandchildren are not as intense as those with your own children, he says.
"You have this wonderful thing with grandchildren where you are on holiday for two weeks, or they come for a weekend. It's fairly carefree. It's not your job to impose discipline, or routines, or say, 'Have you done your homework?'"
What is wonderful, he says, is that his generation are the first who can expect to watch their grandchildren grow into adults. "When I was young most of our grandparents died in their early sixties. They didn't really get to know you nor you get to know them. The age gap separated us much more then than it does now. I was in awe of my grandparents. I don't think my grandchildren are in awe of me one bit."
Is he a difficult person to get to know? "Probably, I don't know," he replies. "It is very difficult to judge oneself. I think on one level no. I love people, I love exchanging ideas, talking, finding out about people, and I think I'm fairly open at that level. But there is a private side to me which I keep quite guarded. It is not a side to me that I like very much but I think writers to some extent have to have this. It is a troubled side.
"As a writer you have to be sensitive to yourself, to the needs in yourself, to the troubles in yourself. It helps you to empathise with other people - Life is complex, and it can be for all of us a slough of despond from time to time. There is no doubt about that, and there is no point in denying that is a side of me. But it is a side of me that I naturally keep quite private." The door has shut politely, but firmly, once again.
Morpurgo's writing mentors are his friend, the late poet laureate Ted Hughes, "and your great countryman, Robert Louis Stevenson". Stevenson, he says, is the person he would most want to be as a writer, because of his variety and his sheer passion for storytelling.
Whether speaking out about children's rights or writing books, Morpurgo is the gentleman pugilist of children's literature, slugging away elegantly for the causes, and the young readers, he holds dear.
The latest project he is involved with is Afghan Connection, a charity dedicated to opening schools in Afghanistan. From Private Peaceful in the First World War to the Afghan conflict, war is always with us. And with Morpurgo. "What is it in the hymn, fighting the good fight? That's what we've got to keep doing." n
Private Peaceful (12A) is in cimenas on October 12. A Medal For Leroy is published by HarperCollins Children's Books, priced £12.99.