Tolworth Court Farm, Surrey: The last splashes of Bonesgate stream trickle into the Hogsmill

On a crisp January morning, when a brisk dander is all but compulsory, a thorough frost has whitened the broad corridor of the Hogsmill’s upper reaches. Dazzling sunshine turns the treetops amber and picks out a collared dove’s blush; but the air feels, smells, barely above freezing.

Thick woollen gloves, two pairs of socks and hefty boots cannot counter the numbness in my fingertips and toes. At the river’s narrowest point I cross and become part of its flow using five round stepping stones. Icy bramble branches contort and curve with a static flail.

A mile on, at the edge of Tolworth Court farm’s grasslands, separated by hedgerows from the Ewell bypass and the shadow of Tolworth tower’s 22 storeys, a moorhen’s big-foot pacing and spillage into the Hogsmill appears even more hesitant than usual, like a child tiptoeing over a pebbled beach.

Field names, including Great Meadow, Dewberry Field, Great Hollands, Grub Close and Finch Hoares, evoke a long, continuous, history: this land has been worked since serfdom, and is still used for hay. Today, under contrailed blue skies, the 43ha (107 acres) of meadow are a sea of freshly desiccated coconut. South-west London contains few landscapes as ripe as this for standing, gazing and imagining how things must have looked in pre-industrial times.

Tolworth Court is already a local nature reserve, but there is talk of designating it a country park. Whether that means a car park, cafe and other visitor-friendly resources, and how its character might change, has yet to be revealed. What is known for sure is the habitat’s importance in supporting species rich in number, variety and local scarcity.

The last splashes of Bonesgate stream, reputedly named during the black death, trickle into the Hogsmill. Like a squeaky toy, the moorhen calls from the confluence’s wash. For once, no unleashed dogs are thrashing around in the shallows.

I skedaddle across Great Meadow, the ice-packed tufts just about supporting my weight so my boots don’t sink within the marshy mud of the track, which slopes upwards, to the gate.