It wasn’t as if I didn’t already have an article neatly mapped out. In it, I tut-tutted at the crass tartanisation I knew that I’d find and pointed out the irony of a fortified city that can’t even withstand an annual invasion of luvvies and alternative comedians. I primly advised against the tourist traps of the Royal Mile but recommended the notorious docklands of Leith with its dangerous streets and intimidating drinking dens. This, I intended to say, is where the visitor with enough bottle to walk on the wild side would encounter the real Scotland, still red in tooth and claw. And a jolly good article, it would have been - that is, if the Edinburgh I found hadn’t stubbornly refused to comply with my expectations.

Take Leith, for instance. The only thing that scared me when I actually got there was the price of the house white in Malmaison, one of the area’s many new chic wine bars, eateries and hotels. In the bad old days, Leith might have run Gomorrah a close second as the place least suitable for tea with your maiden aunt. But the port, like a sinner who has seen the light, is now on his best behaviour, stylishly spruced up and fit for polite society.

Edinburgh, however, remains an unrepentant witch of a city: not the old crone I’d expected, but a femme fatale. I hadn’t anticipated either the classic beauty of the New Town (in Edinburgh “New” means circa 1750) or the spell-binding glamour of the Royal Mile. I’d come as a Witch Finder General ready and willing to pass sentence, and left a schoolboy, hopelessly smitten and swearing eternal love.

I have a headful of images odd moments that I couldn’t have possibly imagined and as incongruous as the town itself. A lone piper, in full regalia, queues in Boots to pay for Strepsils and the other shoppers not paying him a blind bit of attention! A wee old dear in knitted hat sits in the secluded gardens at Dunbar’s Close, reading Nietzsche (Supergran, possibly). A man in pinstripes, striding to the law courts in Parliament Square, pauses to spit purposefully on the pavement. Actually, it’s at The Heart of Midlothian, a motif picked out in cobbles marking the site of the Old Toolbooth which for centuries had housed the town’s death row. Spitting on it, apparently, is how the locals traditionally register their abhorrence of capital punishment.

Even after you’ve walked its streets for two long days, a city of so many contrasts defies generalisations. I was, for example, going to point out how the looming tenements and twisting wynds contribute to a giddy sense of urban claustrophobia. Well, it’s true, but it’s just as true to say that Edinburgh despite its nickname of Auld Reekie-is permanently being tossed in fresh sea breezes blustering in from the Firth of Forth. At times, it can feel less like being trapped in a town and more like being on board some dangerously ramshackle pirate ship negotiating the Cape of Good Hope.

But don’t be misled by this nautical nonsense I could just as easily have written that the city looks in imminent danger of being swamped by countryside. Arthur’s Seat, which towers over the skyline, might not be a Ben Nevis of a mountain but is a suitably stern reminder that no town even the creme de la creme can match the rugged grandeur of the Scottish landscape stretching off to the north. I have to confess that although there are daily minibus excursions to spot Nessie and suchlike, the nearest I got to ye banks and braes were the illustrations which adorn virtually all the knick-knacks in the souvenir shops.

As I had expected, Edinburgh is unblushing in its exploitation of all things Scottish. But rather than deride it as I’d planned to do, I eagerly jostled with the other tourists dithering over miniature bagpipes, knitted Aberdeen Angus, haggis-shaped pencil-sharpeners and enough tartan to stage another Jacobite uprising. We needed some momento of our visit to this foreign country and foreign it certainly seems: being in Edinburgh really does feel like being abroad.

It’s true the natives speak English, but do so in a way that makes it sound perfectly and delightfully their own. When a television was turned on in a pub, I was momentarily taken aback to see that our own Michael Buerk reads the news in their country too and that they actually gave a hoot about what was going on in far-away Westminster. That is, perhaps, the most baffling thing about Edinburgh: it’s a capital city as haughty and as metropolitan as they come but with no independent nation to be capital of; it has two impressive houses for a parliament, and no elected representatives to sit in either.

To discover how this odd state of affairs came to be, all you have to do is walk the Royal Mile from the Castle to Holyrood House. The history is written in an alphabet of unruly architecture. Tenements, patched up and modified over the centuries; some imposing kirks; a few monstrous carbuncles and a welter of garish hoardings designed to attract the constant ebb and flow of perplexed visitors trying to make head and tail of it all. The road (in fact, it’s four linked roads) would be spectacle enough in itself, but it also offers 300 or so entrances to a labyrinthine tangle of narrow wynds, passage-ways, courts and the sort of alley-way you wouldn’t like to go down alone after dark.

Old Edinburgh is exactly the sort of town that a lad with a new box of crayons would want to design, knowing full well that no adult would ever be imaginative enough to let it come into being. Only a boy with a taste for the spectacular would decide on that many proud spires, bold turrets, such a warren of dark hiding places, or a castle on a hill that really does look like a castle ought to look.

It’s not only the architecture that’s Boys’ Own; so too are some of the most memorable attractions: Mons Meg (a cannon big enough to climb into); a museum devoted entirely to toys and games; another museum (on the history of malt whisky) through which you’re transported inside a barrel; the shrine to the Skye Terrier, Greyfriars Bobby official recognition that a boy’s best pal is his doggie. Then there’s the marvellous Camera Obscura simply the biggest, bestest toy any boy could ever wish to have. You sit in a darkened room, and a contrivance of lenses and mirrors, spreads the city out before you, like a patient etherised upon a table.

Seeing it this way, silently going about its business, Edinburgh can seem a benign place. For a moment you forget that its bloody history reads like a particularly gruesome series of penny dreadfuls evidence enough that little boys never grow up, they only grow nastier. Walk the Mile and discover that Edinburgh’s story is merely the chronicle of unremitting gang warfare: clan against clan, mob against masters, Covenanter against Royalist, Catholic against Protestant, Calvinist against Moderate, Hearts v Hibs.

Today, St Giles’ Cathedral might celebrate a God of love, but there was a time when its spikes were adorned with the heads and limbs of those guilty of the biggest crime little boys can commit being on the losing side. Boo sucks. Check out his statue in St Giles’ and you’ll see that John Knox is Just William don’t let that false beard fool you. William’s horror of girls is merely a reiteration of Knox’s tirade against “the monstrous regiment of women”.

While the boys were busy being boys, Edinburgh’s most famous daughter was among the many who suffered the consequences. The Old Town seems as if it had been designed as no more than a flamboyant backdrop against which Mary Queen of Scots could act out the grand opera she made of her life. At Holyrood House (the palace at the end of the Mile) she witnessed the brutal stabbing of Rizzio; heard news of Darnley’s murder; listened to the mob howl “Burn the hoor” and set off on the long journey to Fotheringay and the sad and inevitable last act.

And it was from Holyrood House that Bonnie Prince Charlie noblest schoolboy of them all set off with his troops on the grand adventure that ended at Culloden.

I could happily play truant and walk the Mile for a month or two more but I have to go to grown-up York. This was the town, incidentally, where the Duke of Cumberland returning in triumph from Culloden had his prisoners-of-war publicly executed. I’ll find out exactly where and remember to spit.