The idea immediately came under fire from critics and historians concerned that Scottish art was in danger of being parochialised and ultimately diminished. Such was the furore that an appeal to the Secretary of State for Scotland brought a temporary reprieve.
Can it be mere coincidence that, some 20 months on, the Scottish National Gallery's major Edinburgh Festival exhibition should be devoted exclusively to Scottish painting? "Hidden Assets: Scottish Paintings from the Flemings Collection" presents a picture of Scottish art over the vital period of 1830 to 1930 and, clearly, one of its effects will be to implant deeper in the public consciousness the notion of this national school of painting.
This may not have been the primary intention of the scholarly curators of this well-presented and thoughtful show, and it was probably not that of Flemings. This Scots-owned merchant bank, which operates from headquarters in the City of London, has over the past 30 years built up an extraordinary collection of Scottish art. This policy suggests that the collection is as much a means of preserving a national identity as it is a perk for the bank's employees. Staff and visitors walking past these paintings can be in no doubt as to the bank's origins. This is painting as an expression of nationality.
However, it must have been apparent to the director and trustees of the National Galleries of Scotland that, removed from the context of a private, corporate collection to a public gallery, these works of art would become transformed.
Seen in the Scottish National Gallery, the Flemings pictures attain a heightened coherence, as did the gallery's exhibition of French Impressionist paintings two years ago, or the current School of London exhibition at Edinburgh's Gallery of Modern Art. But Scottish art, of course, is not a "school". Certainly, through the ages Scottish artists have shared certain abiding concerns, and, some would say, certain national characteristics of style and awareness. But, by the period covered here, there were other factors to consider, notably the influence of French and Dutch art, the Enlightenment and foreign travel.
The implications of this new coherence become still greater when one takes a closer look at the Flemings collection. This is a holding of national importance, of such quality that it could itself create an admirable National Gallery of Scottish Art.
The earliest works here, two views by Alexander Nasmyth and John Knox that illustrate the birth of Scottish landscape painting in the 1820s, are followed by three exceptional works by Scotland's greatest 19th-century painter, David Wilkie, spanning his main interests of common life and national history. A gap in the narrative (the lack of works by Geikie, RS Lauder and the Scottish Pre-Raphaelites, Bell Scott, Dyce and Paton) is partially filled by a small version of Tom Faed's Last of the Clan. This, and another picture in the exhibition, JW Nicol's Lochaber No More, are the major contemporary artistic documents of the Highland Clearances, and in terms of cultural identity the most important works in the collection.
Other artists notable by their absence are McCulloch and Orchardson. William McTaggart is represented by three paintings - certainly among his most charming - but it is strange for Flemings not to have included his Machrihanish, Bay Voyach of 1894, a more significant late work and one of the gems of the bank's collection.
It is with the Glasgow Boys and the East Lothian painters of the late 19th century that the collection begins to show its real strength. Particularly notable are two watercolours by Melville, one of Hornel's less sacharrine paintings of young girls, and a fine James Paterson. Five paintings by the still-underrated DY Cameron (of the 30 in the company's collection) restate the artist's position, and there is also a strong group of works by the Scottish Colourists: Peploe, Cadell, Fergusson and Hunter, bought shrewdly before such paintings became unaffordable. The enlightened buying of Flemings' current curator, Bill Smith, is attested to by the most recent acquisition here, James Gunn's poignant Eve of the Battle of the Somme, shown recently in the artist's major retrospective.
These 60 works are a mere fraction of Flemings' collection of 800 paintings and watercolours, half of which are by living artists. It is disappointing that none of these later paintings are on view, but despite the arrant Scottishness of such painters as Gillies, Bellany and Philipson, they make more sense when taken in an international context. Their exclusion might thus suggest an undeclared reason for the apparent cut-off date of 1920. It also acts as a pointer to what is lacking in this show.
Scottish art demands to be seen in the company of the European, and latterly the American, artistic heritage. That is the only way to judge its success or failure. Certainly these are pleasing images, but show us Peploe's Kircudbright without a Cezanne, or his late still-lifes without a Matisse, and we cannot understand his complex stylistic development. Both would have been possible given the gallery's collection. As it is, neither artist is even mentioned in the catalogue entries.
Similarly, we learn nothing of Melville's inspiration by looking at Wilkie, or of John Duncan's international symbolism by a contrast with McTaggart's boldly Impressionist village children.
In his introduction to the exhibition catalogue, Timothy Clifford, director of the National Galleries, arch-architect of the campaign for a Gallery of Scottish Art - and an Englishman - writes: "It is our hope that [the exhibition] will continue to stimulate constructive and challenging discussion on the representation of Scottish art in the National Galleries of Scotland." It is not difficult to read between the lines of this smoothly worded declaration.
The Trustees recently stated their "wish to develop a wide and open consultation process" on the feelings about the proposed new gallery. Here, in this exhibition, that process is in operation. We might almost expect the catalogue to come with a pre-paid reply form, for in effect this display is the substance for a referendum.
Mr Clifford and his trustees have cleverly used this exhibition to do what their opponents cannot. They are out to persuade the public, and here is the perfect way to show us just how attractive, polished and proudly Scottish their new gallery could look. Whether they have done themselves a disservice by revealing the shortcomings of hanging Scottish art on its own remains to be seen.
This undeniably impressive show, whose motive is apparently to celebrate the vision of an enlightened corporate collector, has unsuspectedly great implications for the future of Scotland's art, and should be viewed with extreme caution. This is not as it might seem, merely a Festival exhibition allowing "privileged access" to a famous collection. It seems, rather, to be a disingenuous dry-run for a National Gallery of Scottish Art.
n National Gallery of Scotland, The Mound, to 24 Sept. Details: 0131- 556 8921