Beyond a dense strip of forest, off a narrow single-track road in north west Poland, is what looks to the casual observer to be a man-made fishing lake, or perhaps a small reservoir. But as you approach, an appalling stench and a giant factory-style building begin to suggest otherwise.

This is no ordinary lake. It is an open cesspit, a vast lagoon full to bursting with waste from the nearby industrial-scale pig farm. Floating beneath the surface of the lagoon are the bodies of an unidentifiable number of dead pigs in various stages of decomposition.

Until their carcasses are prised out of the waste they are almost unrecognisable aside from the odd snout and curly tail visible in the filth. Everywhere is the detritus of factory farming — plastic syringe casings, intravenous needles and white clinical gloves — floating in the rancid pool and discarded on adjacent farmland.