So we’re here, in the serene and relatively intact harbour environment at Leigh, to film human impact where the water remains clear enough to get a picture, but where our influence is becoming obvious.

Jack mackerel circle about the wharf piles, while the discards of civilisation rot quietly on the seafloor. An octopus has made a home in a car tyre, and mud accretes slowly over consumer electronics. It’s an unhappy scene, but in reality, orders of magnitude better than elsewhere in the gulf.

Cities are plastic pumps. It’s a wonderful material—strong, light, versatile, recyclable—but it belongs nowhere near the sea. Plastics entrap, foul and poison marine species, they are very slow to break down, introduce contaminants when they do, kill organisms that digest them and persist for decades. Enough already.