Upriver of Calstock, within one of the Tamar’s many meanders, polleny grasses and flowering rush intersperse with gullies and lagoons in a new wetland – for flood defence and conservation. On this dull afternoon, swallows dip above shallow pools and the chirruping of unseen birds, emanating from the recreated marsh, sound different from familiar woodland songs.

Outside the soughing reedbeds, on the ebbing tide, a double-masted yacht secures a mooring in the channel beneath Buttspill Wood, and by Tuckermarsh Quay a little steamboat puffs quietly downstream towards a gathering of enthusiasts’ craft. Ahead, Okeltor mine engine house and chimney are almost obscured by trees. Nearer, another monument to former industry is a trio of defunct limekilns with granite arches and cave-like interiors dripping limey water from dainty stalactites.

On the higher side of the wetland, Harewood Road leads back to the riverside port, so busy when goods and produce were transported up and down the sinuous waterway, miles inland from the sea. Today’s visitors eat ice-cream, drink outside the Tamar Inn and, between showers, stand about admiring the steamboats, Plymouth morris dancers and flotillas of ducks.

A narrow road continues downriver beneath the railway viaduct, alongside terraces of houses and retaining walls draped in Mexican fleabane. Towards the confluence with the Danescoombe stream, tendrils of old man’s beard mask more limekilns below the embankment of the disused incline railway, which once lowered ore, brick and stone towards the riverside quays.

Away from the river, overhanging trees darken the narrow tributary. Overgrown market gardens and plots of the local double white narcissi blend with shaded woodland, with its undergrowth of hard fern and woodrush. Remains of the Cotehele Consols mine include the engine house, its ruin restored and converted into a secluded holiday let; the cottage’s name, Mispickel, reminds of the arsenic ore that was produced here.

Returning to higher land, we glimpse the 5.10 train to Gunnislake crossing the viaduct, as the Ferry Farm dairy herd walk towards their riverside pasture, in single file along the Devon bank.