According to the BBC, Mr Shepherd took his passport out to check its validity ahead of the trip. He then left it out on a table. Big mistake.
"When I got back I saw pieces of paper on the floor and didn't know what it was. Then I saw him on the bed with the passport in his mouth," Mr Shepherd told the BBC.
"I was in shock, I didn't know what to do."
"We also have a seven-year-old cocker spaniel called Honey, and she left the passport alone, but Mr Boots fancied chewing something, so he had a little bit of that," he told Cornwall Live.
"You can give him all the toys in the world, but he still wants something else."
But there's a happy ending to this story. While a new passport can take weeks to get, Mr Shepherd told the BBC "the authorities agreed to speed things up and help out as I was representing my country."
Of course, he did have to make an eight-hour round trip to the nearest passport office.
And as for Mr Boots? Turns out he put his "puppy-dog eyes" to good use.
"It's my fault, I left it on the table," the BBC reported Mr Shepherd saying. "You can't be mad with a puppy, can you?" Click for more trending news