THE 15th-century cobblestone bridge crossing the river Doon at Alloway, looks idyllic and picturesque by day and in most tourist photographs, or even on our crisp £5 notes, but, of course, it has another darker, and more dramatic life in the imagination of Scots, and those the world over who have enjoyed our bard’s tale of Tam O’Shanter.

It is an icon of the supernatural and local superstition. A beguiling reminder of the weird and uncanny.

In our mind’s darkness, witches tear towards it. A grey mare pounds, tail flying in the wind and rain. Nan, leaps to clutch the. This is the place, famously, to which the drunken Tam fled on his mare, Maggie, pursued by this “hellish horde”, knowing that “a running stream they dare na cross”.

For Robert Burns great narrative poem wasn’t purely invented. It was based upon a local lore and story, recorded in a letter to his friend, the art critic and antiquary Captain Francis Grose. There were Burns notes in this epistle, three witch stories associated with the Alloway Kirk. Amongst these “authentic” tales was that of a Carrick farmer who saw a witches’ dance in the haunted kirk and had to flee for his life with witches and warlocks at his horse’s tail.

“I need not mention,” writes Burns, “the universally known fact, that no diabolical power can pursue you beyond the middle of a running stream. Lucky it was for the poor farmer that the river Doon was so near, for notwithstanding the speed of his horse, which was a good one, against he reached the middle of the arch of the bridge and consequently the middle of the stream, the pursuing, vengeful hags were so close at his heels, that one of them actually sprung to seize him.”

By day Brig o’ Doon, is almost too neat and picturesque – just above the Brig, an ornamental garden, with nine pillars representing the muses – the setting so manicured in its topiary, it feels as if it must hide something, even now, a little darker. Which, of course, so many places do, when the sun falls over the horizon and we turn to drink, or find our minds a little altered.

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The Brig and its horror-filled story seem to symbolise the fine line alcohol takes us to between glory and disaster. As Burns wrote in Tam O’Shanter’s final lines: "No, wha this tale o' truth shall read/ Ilk man and mother's son take heed/ Whene'er to drink you are inclin'd,/ Or cutty-sarks run in your mind,/ Think! ye may buy joys o'er dear - / Remember Tam o' Shanter's mare."