Fostering guide dogs was part of Gary Lyon’s plan to never get his heart broken again. It backfired spectacularly. It all started when Lyon, a 75-year-old retired plant pathologist, had to put down his pet dog, Zac. “He was a lovely boy,” says Lyon. “But he had all sorts of health problems towards the end, and was off his feet and not happy.” Zac, a lhasa apso, always had a very responsive tail. When it was up, he was happy; when it was down, he was sad. “We noticed his tail was down all the time,” says Lyon, “and realised the end was nigh. After it was done, my wife Carol and I said we never wanted to go through that again.” It is the first of many times in our phone call that Lyon almost cries. Lyon lives near Guide Dog UK’s dog training centre in Forfar, north of Dundee, where puppies finish their training before being rehomed. “I’d seen people locally with guide dog puppies,” says Lyon, “and thought, ‘That’s a good way to go. That way, I don’t ever have to put another dog down.’” He signed up to be a trainer in 2014. For the first year of their lives, puppies live at Lyon’s home. He teaches them basic commands and more complex skills, such as how to lead people upstairs and how to stop at a curb and wait for the lights to change. “Guide dogs are some of the best-bred dogs,” says Lyon. “If there are any medical or behavioural issues, their parents are taken out of the breeding programme. They’re intelligent, inquisitive, confident.” Most are labradors, golden retrievers or German shepherds – or a mix of these breeds. One of the first dogs Lyon trained was Elvis, a labrador. Lyon taught Elvis how to identify a door. “What you do,” he says, “is say, ‘find door’, go to a door, rattle the handle, then give him a treat.” To test him, he took Elvis to a shopping centre in Dundee. “I said, ‘find door,’ and he took me to the nearest exit. We hadn’t even come in that way. I had no idea how he did it. I think he smelled the fresh air.” When he started working with Elvis, Lyon thought it would be easy to give him back. (Lyon usually gets the puppies when they are seven weeks old, and hands them back to continue their training when they are 14 months.) “When we first got Elvis,” Lyon says, “people said, ‘Won’t it be hard to give him up?’ We said, ‘Oh no, it’s not like putting a dog down.’ I had no idea. I just disintegrated when the dog went.” He chokes up again. The next dog Lyon trained was Murphy, a lab-retriever cross. “He was so cute it was unbelievable,” he says. Murphy went to Sarah Parkinson, who is 55 and lives in Newtongrange, just outside Edinburgh. “I became very depressed when my eyesight deteriorated about five years ago,” says Parkinson. “I had to give up work and felt completely confined to the house. But when I got Murphy life just started getting better. He enabled me to live a full life again. He’s changed my life completely.” Lyon, she says, is a truly remarkable person. “He’s so dedicated,” she says. “He produces such rounded dogs. They’re so loving and caring and well-trained.” Parkinson, Lyon and Carol are now friends: she comes to visit, and brings Murphy with her. Watching Murphy interact with his new owner is a bittersweet joy. Murphy looks up at Sarah with such love, Lyon tells me. He is emotional again. After Murphy, there was Rocky, a German shepherd. “God,” says Lyon, voice cracking. “He was lovely. I bonded with him big time. Floods of tears when he went.” The most recent dog was Forest. “He was the best,” says Lyon. “He was stunning. My wife bonded with him and said, ‘I can’t do it again.’” It’s a bitter irony, I point out, that a plan to avoid the heartbreak of putting down another dog has locked Lyon into a perpetual cycle of loss – only with many animals, not just one. “I am torturing myself,” he agrees. “But it’s worth it.” He says it is a privilege to train the dogs. “I’m doing something useful. You can’t always do something useful in life.” When asked about his treat from Guardian angel, Lyon is resolute: the only thing he wants are some fresh toys for his current charge, Danny, a 13-month-old labrador-retriever cross. “He loves soft toys,” Lyon explains, “but they don’t last long.” Online pet boutique Love My Human provides Danny with a box, which the puppy immediately gets to work on. “He’s shredded one of them already,” says Lyon. “It was a pig. There’s only a tail left now.” They’ve been playing tug-of-war with the remaining toys: it takes all of Lyon’s effort not to fall over. “They’re such strong dogs,” Lyon says. Watching Danny gambol and play with his new toys is a bittersweet experience for Lyon. “I’m not yet dreading him leaving,” he says. “That comes later, when they’re getting ready to go. I just want him to succeed.”