There are online marketplaces for luxury brands, secondhand fashion and street wear. Why not for sustainable style? So wondered Agatha Lintott from her remote farmhouse nestled in the green rolling hills of the South Devon countryside in England.

Ms. Lintott, a former teenage model and previously a women’s wear buyer for Tom Ford and Burberry left Burberry in 2014 to start a new life far from London with her boyfriend, Ben Howard, an award-winning, folk-influenced English musician.

“I felt quite disillusioned by all I had seen in my years in the business,” said Ms. Lintott, clad in a black T-shirt and black flared hemp pants, long brown hair falling down her back, over a recent lunch of grilled haddock and squid. “I realized that I didn’t know of anywhere on or offline that really inspired me to shop ethically or that offered me a range of items that I could feel proud about buying.”

So, from her kitchen table and with a full-time team of just three employees based across Milan, Devon and London, she decided to do it herself. She envisioned, she said, “a hub for earth- and human-friendly fashion across both vintage and new labels, that would also debunk this lingering idea that sustainable fashion was unglamorous.” In April of this year, Antibad went live.