So many films have been made that traded in Scottish myths. So many Hollywood representations — from Brigadoon to Braveheart — have either been derided or taken with a huge pinch of salt by film lovers in Scotland. So many directors have suffered when they have tried to distil the essence of the country on to celluloid. The film-maker who deals in Scotland must be prepared to be bitten — especially when a particular small terrier is involved.

We are in Stirling where the new film about the old dog, The Adventures of Greyfriars Bobby, is being shot. The £6m independent production has assembled one of those quietly stellar casts that more typically adorn a BBC costume drama.

Here, Ian Richardson, bouncing on tip toes in his judge’s pumps, is making mischief. “Oh I don’t think you want to be shaking hands with me,” he says, “I’ve just been picking my nose.” There, stepping from his car in the shadow of the castle, is Christopher Lee, still imperious at 82 with his gold fob and frock coat. He must be happy to do a graveyard scene without the fangs.

The cast are unusually well acquainted with the Bobby story. Ardal O’Hanlon, almost unrecognisable under his rags and sporting the kind of fake beard ZZ Top would have killed for, is recalling his first Edinburgh Festival, performing at half past midnight at the Greyfriars kirkyard.

Lee, who is playing Sir William Chambers, the lord provost, declares he has seen the statue many times when he has come to play golf at his club outside Edinburgh. Greg Wise recalls drinking in the Greyfriars Bobby pub when he was an architecture student in the city. For Richardson the tale of the faithful terrier was part of an Edinburgh childhood.

THE question is, though, what story? Bobby’s reputation is a curious mixture of fact and fiction. For that we have to thank Eleanor Atkinson. In 1912 the Indiana-born magazine publisher decided to write a novel based on the dog’s exploits without ever visiting Edinburgh. Such impudence condemned her to almost a century of condescension in Scotland. Greyfriars Bobby became almost a byword for a certain kind of American sentimentality and is still written off as a saccharine Edwardian period piece by people who haven’t read it.

“There’s always been a resentment about the American version of Greyfriars Bobby,” says Henderson. “There’s a Scottish children’s book I’ve seen that tells Bobby’s story and you turn to the last page and it says something like, ‘Then an American woman came along and made up all sorts of things’.” A 1960s Disney film of the story was rather subtitled “the true story of a dog”.

It is true that Atkinson portrays an auld Edinburgh filtered through the works of Sir Walter Scott, with a dash of Dickens thrown in for good measure. Her Scotland is a place of bluff but good-hearted innkeepers and lovable urchins.

But the idea that she was purely a sentimentalist is wrong, and if the new film is true to her account it could deliver a surprisingly large quantity of that most unHollywood of qualities: gritty realism.

The Edinburgh Atkinson describes — sight unseen — is no Disney fairy-tale landscape. Outside the doors of Mr Traill’s warm inn, where Bobby sits at the feet of Auld Jock, his master, the streets reek of poverty, disease and crime.

When the market closes, Atkinson’s bustling Grassmarket reveals its sordid side. “Beggars and pickpockets swarmed under the arches of the bridge to swell the evil-smelling human river that flowed at the dark and slimy bottom of the Cowgate,” the author wrote.

Why should an American woman have cared about any of this? If your aim is to write a simple tale about “the very youngest and smallest and shaggiest of Skye terriers”, the social history of Edinburgh should hardly matter.

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