Thomas Marks.

When we meet, Country Mouse is all talk of Appleby Fair, of the mutter of horse-dealers and the leathery smell of the animals. It’s his enthusiasm, paired with a visit to The Horse: from Arabia to Royal Ascot at the British Museum (until 30 September) that has me watching for horses and their ghosts in London this month. Sitting in the quiet July dusk of Canonbury Square, it’s not long before I imagine the clean clip of hooves in the distance.

The art and artefacts on display in the British Museum tell of the historical journey taken by the thoroughbred: from ancient Middle Eastern civilizations to polished English worlds of sport and leisure. But the city of horses that has started to haunt me is a place of work and transport, of powerful animals slogging at tasks that have long since disappeared or been motorised: the omnibus and cab horses, the brewer’s dray, the coalman’s sturdy nag. In Thomas Rowlandson’s riotous caricatures of Regency London (above) or Doré’s infernal engravings of the city, its streets are chock-full of working animals. Examining ‘the horse world of London’ in 1893, one writer estimated that the city’s herd numbered as many as three-hundred thousand.

‘And at the corner of the street / A lonely cab horse steams and stamps’: when T.S. Eliot saw that solitary beast in his ‘Preludes’, he was wise to how the horse-powered way of life was retreating. Nowadays, horses in London seem rare and unnerving. We have all watched them skittering at protestors on the evening news. But they can also bring that dream-feel that comes when the countryside appears to jostle with the city: the dawn-trot of a police troop on its exercise route through Hampstead is as magical as a sepia photograph come to life.

While most of the horses have gone, equine traces linger in London’s architecture and street furniture. Think of all those uptown mews, their once inconspicuous stable blocks now translated into elegant housing. Or of leftover horse-blocks and hitching posts, or the walls scuffed along the Regent’s Canal where towropes once left their mark. Whenever I peer up at street signs, I think how they were first installed so high to suit the sight line of hansom-cab drivers. And the street names themselves remember horses, horse provender, horse paraphernalia: Mare Street, Haymarket, Bridle Lane.

The city’s equestrian statues speak of a grander world of pedigree and achievement. But recent sculptures rethink what it means to take the horse as a monumental subject. The golden rocking-horse now on the fourth plinth in Trafalgar Square shows the glory of not power but play, while the obstinate stallion that strides through the Animals in War Memorial on Park Lane seems to have shrugged its rider. Older sculptures look different now too, in a city that has lost its vast herd of horses: the rampant bronze quadriga on the Wellington Arch might be taking flight, as if the last of them were bolting London for ever.