How the publishers of this remarkable volume must have hugged themselves when Wendy Alexander, the leader of the Scottish Labour party, recently thrust her hand into the hornets' nest of Scottish independence. On the face of it, a book on the history of Scotland by an academic who died five years ago is not the most marketable of items. But now it has a topicality that should propel it straight on to the bestseller lists. It was first drafted in the mid-1970s as part of Hugh Trevor-Roper's campaign against Scottish devolution. Once that danger was nullified by the election of Margaret Thatcher in 1979, he could lay the manuscript on one side and move on to the more urgent business of making a mark in the House of Lords, to which the new prime minister had promptly elevated him.

Now that outright independence is the issue, the book's polemical purpose has a fresh urgency. It sets out to strip away the layers of myth that encrust three of the main components of Scottish identity: historical, literary and sartorial. All nations have their myths, of course, but, in Trevor-Roper's vigorously expressed opinion, the Scots are in a class by themselves when it comes to creating a fictitious past. Nothing if not audacious, the medieval chroniclers found the original Scottish hero in the Greek prince, Gaedil Glas, who married a pharaoh's daughter named Scota. Fleeing from Jehovah's chastisement of the Egyptian persecutors of the children of Israel, they made their way to Spain, from where their descendants moved first to Ireland and then, in 333BC, to Scotland.

This was not to be the last time that the Egyptian connection contributed to Scottish history. In the early 16th century, Hector Boece, the Aberdonian humanist, recorded proudly that in the second century BC, Ptolemy II had sent envoys to his Scottish kinsman, including in their baggage the works of Aristotle, which the cultured Caledonians hastened to read in the original Greek. Boece also filled in an awkward lacuna in his country's genealogy by the simple expedient of inventing 40 kings covering 22 generations, complete with detailed biographies for each. They were presented in a contrapuntal sequence of heroes and villains, the latter exemplified by the vile King Lugtachus, who mixed murder with incest, repeatedly raping his aunts, daughters and sisters before moving on to their various offspring.

Of course there were dissenting voices. But Trevor-Roper insists that, whereas in other European countries these fanciful “histories” could not survive the critical eye of the Renaissance humanists, in Scotland “the whole troupe of primitive Scottish kings, so happily refloated and redecorated, would sail in their newly gilded ship, to the accompaniment of flutes and hautboys, like Cleopatra on the Nile, down the sacred river of tradition, while devout cheers arose from either bank: from Left and Right alike”. This single sentence is sufficient to demonstrate the literary qualities of this book. Even when Trevor-Roper is dealing with the less than riveting details of medieval historical scholarship, he is a pleasure to read. The prose is elegant, the argument incisive, the tone ironic.

Patrician disdain is also on display when he turns to literary myth-making. With the Union firmly established by the crushing of the Jacobite rebellion of 1745 (“'the last fling of an archaic society, already on the verge of dissolution”), Scots turned to culture to express their separate identity. An early example was the Rev John Home's tragedy Douglas, which enjoyed a brief success at Covent Garden in 1757, inspiring a Scot in the audience to cry out, “Whaur's your Wully Shakespeare noo?”

That proved a false dawn. Much greater staying power was shown by the epic poems of the Celtic bard “Ossian” published in the 1760s by James Macpherson. Claimed to be compiled from recently discovered ancient manuscripts, in reality they were almost entirely the work of Macpherson himself. In Edinburgh, men of letters fell on this evidence of an immemorial literary culture with delight. Even after so prominent an intellectual as David Hume had declared that the opinions of “50 bare-arsed Highlanders” would never persuade him of their authenticity, Ossian's reputation - and Macpherson's fortune - grew and grew. In London, Sheridan opined that Ossian excelled both Homer and Virgil. In Germany, Goethe sang his praises. Napoleon took his poems on both his first overseas expedition (to Egypt) and his last (to St Helena).

It is at this point that the limitations of Trevor-Roper's demythologising project become apparent. His own view, expressed with characteristic trenchancy, is that Macpherson's Ossianic epics were complete rubbish, “totally unreadable...of inexpressible tedium; its characters as bloodless as the ghosts who provide its supernatural machinery”. Everyone to his own taste, of course, but the range and durability of the responses to Ossian suggest that there was more here than a cynical fraud. There was both more literary merit and more historical substance behind the myth than Trevor-Roper allows.

He is on firmer ground when he turns to sartorial myth-making. In two wonderfully entertaining chapters he exposes just how recent were those two Scottish symbols, the kilt and the tartan. The former was invented in the 1720s by an Lancastrian iron-master seeking a form of clothing for his Scottish workforce more practical than the traditional belted plaid, or cloak. After the kilt's prohibition as a symbol of Jacobitism in the aftermath of the '45, it was taken up by the elites as an emblem of Scottish identity. This association was then consolidated by the same sort of romantic and nationalist impulses that fostered the Ossianic myth. Ironically, the kilt was also given a boost by the exemption of the army from the ban. Within a few years, the tradition was well and truly established that Scottish regiments had been wearing it since time immemorial. As it was they who then became the sharp end of the rapidly expanding British Empire, their kilts became the most distinctive sartorial sign of nationality in the world.

The tartans now associated with the clans were bought off the peg from an enterprising Bannockburn haberdasher in the early 19th century. Once “authenticated” by a clan chief, a particular design could be applied to kilts, plaids, bonnets, biscuit tins and all the other souvenirs flowing out of the newly romanticised Highlands. A tartan that started out simply as “No.155” was first authenticated by Clan Kidd before being taken over by the Clan MacGregor. The whole industry expanded mightily following the visit of George IV to Edinburgh in 1822, when he appeared swathed in acres of Royal Stuart tartan. As one observer complained “the whole land was tartanised, in the royal eye, from Pentland to Solway”. The tartans were then codified by two English brothers who started out as John and Charles Allen, then “scotified”their names as Hay, before finally promoting themselves to royal status as John Sobieski Stuart and Charles Edward Stuart with the claim that their father was the legitimate son of Bonnie Prince Charlie and thus King Thomas I of Great Britain. This material on the kilt and the tartans was first published back in 1983, but fits the rest of this volume very well. It is to be hoped that Trevor-Roper's literary estate contains more unpublished gems.

The Invention of Scotland by Hugh Trevor-Roper
Yale £18.99 pp282

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