As he watched, it veered to the right and scooped up a mound of dogfruit that could only have exited a Great Dane, and recently, by the look of it.

It slipped a Teflon-coated spatula under the offending pile, then squirted a small pool of disinfectant and water on the spot, a rotary brush swirling the last vestiges away, before moving on. The emulsifying unit inside was blending the water, soap and dog turds to a fine slurry. Pasteurisation killed off any parasites and pathogens,

The machine turned the corner and headed across the lawn, to bury a probe into a garden bed. Once the probe was in a powerful pump injected the nutrient rich fertiliser into the topsoil, bringing new life and hope to the plants there.

Roland sighed, wishing he'd invented the things. They were everywhere, these days.