Rachel Joyce in conversation about The Unlikely Pilgrimage of Harold Fry

The Unlikely Pilgrimage of Harold Fry is one of those special books that only comes along once in a while. Male or female, young or old, I can’t think of anyone who wouldn’t love it.

Rachel Joyce’s debut novel has inspired such devotion that on a drizzly Monday night (World Book Night, in fact) scores of us grabbed our umbrellas and dashed off to Abingdon Library in Oxfordshire to hear more about her writing.

Rachel was introduced by Alison Barrow, director of media relations at publishing house Transworld, who confided that during the course of her 25-year publishing career she has never experienced “such love for a book” from readers.

The Unlikely Pilgrimage of Harold Fry is the touching, uplifting story of a man in his sixties who leaves home one morning to post a letter to Queenie Hennessy, a friend he hasn't seen for 20 years. She's dying, and on the spur of the moment he resolves to walk from one end of the country to the other to see her. He has no walking boots, no map, no compass and no mobile phone, but he’s adamant that he’s going to keep on walking till he gets there.

Rachel, a tiny figure with a mass of dark hair, started her career as an actress. Over the past 16 years she’s written more than 20 original afternoon plays for BBC Radio 4 and, as she told us this week, The Unlikely Pilgrimage of Harold Fry began life as a radio play. She starting writing it for her father when he was dying of cancer - "but I'm not sure he knew." After it was broadcast she realised that there was a lot she hadn’t said in the play “that I wanted to say” and decided to turn the 7,000-word drama into a 100,000-word novel. Best of all, it meant she could write about what was going on in her characters’ heads, which she couldn’t do in a play.

It took her a year to write the book and she had no idea if anyone would ever read it. As she explained: “Just as Harold’s walk was a leap of blind faith, so writing the book was for me.” She'd throw herself into writing the moment her four children left for school each morning and was completely taken over by it. Sometimes, when she got ideas while she was driving, she’d ask her children to jot them down for her. “I couldn’t stop thinking about it,” she said. “It was like having knitting in my head. You know you won’t have any peace till it’s done. I felt I had to write a book with my heart in it – true to what I feel, true to what I see, true to what I love.”

Rachel is ultra-disciplined when she’s writing. She works in a shed (now painted “an aesthetically pleasing pale blue”) in the garden of her Gloucestershire home. “But sometimes I have to be at the kitchen table,” she said. “And I have sometimes been known to write at the cinema while my children are watching a film.”

From Harold Fry’s starting point in Devon to his Berwick-upon-Tweed destination, Rachel writes beautifully about the English countryside.  A Londoner by background, she moved out of the city when, pregnant with her third child, she suddenly found herself pushing a buggy across the South Circular to get to “a tiny green patch.” Now she and her husband live on a farm in a peaceful valley - she’d left her children at home that evening feeding four orphan lambs. “When I was writing the book I was writing about my feelings about the land and the sky,” she said. “I increasingly don’t want to be inside.”

The Unlikely Pilgrimage of Harold Fry by Rachel Joyce (Doubleday, £12.99)

PS. A huge thank you to the lovely staff at Abingdon Library for saving me a ticket.