The Kelpies. Scottish Icons by Rab McNeil

So, what have we got here? We have two 98 ft-high, 300-tonne horse-head sculptures depicting shape-shifting water spirits from Scottish folklore called “kelpies”. The etymology of kelpie is unclear but the word may derive from the Gaelic “cailpeach” or “colpach”, meaning “heifer” or “colt”.

Living in rivers, streams and lochs, I’m afraid they were rather malevolent, luring decent rate-payers into the water and even arguably causing floods. It was said they could shape-shift into the form of handsome humans, and therein lies their possible imaginary origin: mothers used them to warn their daughters against men who might lead them astray.

READ MORE RAB: Westminster sketch: I have nothing to offer you but tripe, drivel and mince, pleads PM

Similarly, parents could use the tales to frighten their children away from potentially dangerous waters. See? There’s a purpose to everything.

That purposeful folklore fixed the beasties in ancient Scottish memory, recalling happier times when we stravaiged hither and yon in nature before the age of the machine. But it’s the age of the machine, and of Irn-Bru, in which our latter day Kelpies are located. For they celebrate the heavy horse of Scottish industry, and their place in particular in the economic history of the Falkirk area.

The original idea was that, since the mythological beasties possessed the strength and endurance of between 10 and 100 horses, depending on whom you disbelieve, an analogy could be made with the strong, forbearing workhorses which played such a central role in transforming the area’s landscapes, hauling barges on its inland waterways, taking loads to and from the coal-ships and, in the process, solidifying hard-working, stoical communities.

The Kelpies, illuminated spectacularly at night, can be found between the spa towns of Falkirk and Grangemouth, in The Helix, an 800-acre parkland project created to connect 16 local communities. The massive sculptures are positioned either side of a specially constructed lock and basin that extended the Forth and Clyde canal.

Glaswegian sculptor Andy Scott, who had previous equine artistic experience with his Heavy Horse beside the M8, took the original kelpies idea and moved it “towards a more equine and contemporary response, shifting from any mythological references towards a socio-historical monument intended to celebrate the horse’s role in industry and agriculture as well as the obvious association with the canals”.

On his equine journey, he’d been delighted to discover that, in the 1930s, a huge Clydesdale called Carnera – said to be the world’s largest horse – had hauled delivery wagonsloads of Barr’s Irn-Bru around Falkirk.

His models for the Kelpies were two Clydesdales called Duke and Baron. In 2008, Scott created 10-ft miniature versions in his Glasgow studio. These were then scanned by lasers to create two precise 3D digital pictures to help the steel fabricators create full-scale components, a method used by modern shipbuilders.

READ MORE RAB: Robert the Bruce and Bannockburn: Scottish Icons

The sculptures are composed of hand-cut steel plates welded to a framework of steel bars with stainless steel cladding. With construction completed by October 2013, the Kelpies were launched on an open-mouthed public in April 2014, in a ceremony that featured special effects such as towering flames of fire, light and video projections, to the accompaniment of a sound-track of real horses.

The launch of the Kelpies coincided with the opening of the John Muir Way, a 134-mile coast-to-coast trail through Falkirk and central Scotland, which was named after the naturalist born in East Lothian on 21 April 1838 (subject of a future Icon feature, he played a pioneering part in preserving the wildernesses of the United States).

The Kelpies, named “Scotland’s national treasure” by the National Lottery, were visited by one million people in their first year, prompting Andy Scott to say: “I am particularly pleased as it demonstrates the regenerative effect iconic public art can have, and it seems to have created an almost tangible sense of civic pride in the local area.”

Needless to say, there’s a cafe and gift shop – the Horsebox – not to mention an adventure zone and splash play area. Visitors can even get in their high horse, on a tour that takes them within a Kelpie to examine the engineering bowels of the beast. Two sets of 1:10 scale maquettes have helped to play an ambassadorial role, being displayed locally, nationally, and internationally at venues including Grant Park, in Chicago, and Bryant Park, in New York.

The Kelpies are widely loved. Their liveliness, grandeur and grace have an instinctive appeal, making it hard to conceive of someone disliking – even hating – them. But somebody did. Under the headline “The Kelpies: why Scotland’s new public art is just a pile of horse poo”, Jonathan Jones described the work in The Guardian as “big” – correct – and “bold” – that’s accurate – and, er, “rotten”. Ouchy.

Comparing the sculptures unfavourably to the “exquisitely illustrated” notes made by Leonar-do da Vinci for an unfinished big bronze horse, Jones concluded that the Kelpies were “merely banal and obvious”.

He asked: “Does such a bland sculpture even deserve to be called art?”, and added: “I feel like crying that someone spent £5m on this piece of trash.”

I’ll be candid with you here and confess I’m unqualified to tell whether Jonathan was making valid aesthetic comments from the informed vantage point of the professional art critic. Perhaps he was. Perhaps most “public” art lacks the “difficulty” that he seeks.

But, elsewhere, the Kelpies remain difficult to dislike. The Scottish public, certainly, have taken them to their hearts. They don’t just consider them beautiful. They learn something from them.