During a family gathering this week

my father and I took turns to relate the story about how he came to visit me in France in the early eighties: I was working as a goatherd in a remote woody-hilly place somewhere near the Pyrenees and had sent a letter home describing the route to get to my hut, it was illustrated with a map and my father used it to pay me a visit. *

it was a good story with lots of adventures  - there was one part that I had never heard before:

My father left me to get on with my goatherding and went off to do a few days walking in the area by himself. The first night he stayed in a B&B then continued on his way. A few hours into the day's walk he stopped by a hedge on a dirt track to scrump a few cherries when a van hove into sight and stopped next to him, there were two men inside - one from the previous night's boarding house, this man leaned out of his window and said   

Monsieur, you left this at our 'ouse

and handed over some greyish white fabric that my father recognised as his own, rather unfashionable, underpants

* the map and another version of this story is here