THERE is a stark contrast unfolding between two 19th-century houses on neighbouring Hebridean islands. One is the subject of massive restoration and renewal to create an exciting research and interpretation centre for an amazing collection of items. The other, it has been suggested this week, should be left to fall down, to create a decaying monument to the suffering of the Highlands and the excesses of landlordism.

Canna House was the home of John Lorne Campbell and his American wife Margaret Fay Shaw who were Gaelic language activists, historians, folklorists, environmentalists and obsessive collectors. Campbell bought the island in 1938 but in 1981 he gave it, along with the house and all its contents, to the National Trust for Scotland.

After a long debate regarding how these treasures should be cared for and made more accessible (suggestions included moving the archive to Uist), a massive and imaginative programme of preparation for re-use is now under way involving specially constructed, temperature-controlled, temporary storage on the island.

Canna House – built in 1863 – would not, as the National Trust admits, look out of place in a Glasgow suburb, but that could never be said of the other building in question: Kinloch Castle on Rum. It was commissioned in 1897 by Sir George Bullough, a massively wealthy playboy whose money came from the exploitative cotton mills of Lancashire and whose father had bought Rum in 1888.

The National:

Canna House as photographed in 2008 by Michael Russell

Kinloch Castle was full not of manuscripts, books, music and natural history collections, but of expensive gestures such as a heated aviary for exotic birds, a pool for alligators and an orchestrion (a massive musical instrument that can reproduce the sounds of a complete orchestra), while it looked out on to a nine-hole golf course and gardens laid out using half a million tons of soil imported from Ayrshire.

Bullough and his French wife entertained lavishly and louchely on an island whose entire population were there only to serve his needs. In 1958, 20 years after he died, his widow sold the island to the then Nature Conservancy, retaining only the family mausoleum. This was the second such structure, as Bullough had instructed the dynamiting of the first because it was not grand enough for his and his father’s internment.

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I once spent a damply uncomfortable night in the decayed splendour of Kinloch when I was environment minister, one of several visits I made to the island in response to a plea for help from Scottish Natural Heritage, the successor body to the Nature Conservancy, which was faced with an endless drain on its resources caused by the castle – operating as a hostel – as well as the urgent need to improve conditions for the small resident community.

Keeping the pattern of the Bullough days, they were all employed by SNH because Rum was and still is a national nature reserve with a number of important designations as well as being the home to a long-term study of the island’s red deer herd.

To secure any meaningful future, the lack of diversity in housing and employment needed to be resolved, and I asked Lesley Riddoch, who had been closely involved with the community purchase of the neighbouring island of Eigg, to help find a way forward.

Thus it was that in 2009 the ownership of the village and the glen was transferred to a community trust after a ballot of those who lived there. Now crofts have been established and the population is higher than it has been for some time, although more people and housing are still needed.

The castle was quite deliberately not part of the buy-out. At that stage it was estimated that around £4 million would be needed to stabilise its metal frame which is rotting and in time will collapse, taking the Arran sandstone crenellations and the rest of the building with it. Saddling the community with such a liability would have been foolish.

The Prince’s Regeneration Trust had expressed an interest in taking on the task in order to create high-quality holiday accommodation and plans had been drawn up – but in the absence of funds from the Scottish Government, no transfer proved possible.

That has remained the case and now the cost would be even greater, to be spent on a building with no likely future purpose and no great architectural distinction. Moreover, even if a private buyer could be found, would more external ownership, no doubt supported by public grants for restoration, be anything other than a repeat of the errors of the past?

Fortunately, another suggestion has now entered the lists. Fraser MacDonald, who lectures in geography at Edinburgh University, has suggested that the castle be left to collapse, suggesting that a state of “curated decay” would provide Scotland with a much-needed memorial, testifying to the horror of the Clearances – Rum was cleared in 1826 and 1827 – and the persecution of the Gael, but also asserting the regenerative force of nature.

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There are a lot of practical issues that would need to be resolved, not least the making-safe of the site, but the idea is much more attractive than the prospect of spending up to £20 million – as MacDonald puts out the entire budget of the Scottish Land Fund – on yet another extravagant venture which would of course be justified by some as “providing employment” but which in reality is unsustainable in human, economic and environmental terms.

I have had my differences with the National Trust for Scotland but they cannot be faulted on their commitment to Canna. Of course, that is a place where the past was, and is, being used to inform and improve the present by creativity, humanity and culture.

Rum – the very name of which Bullough tried to change to suit himself – could become the same. All it would take is the courage to speak out, tangibly and visibly, about past wrongs, and be prepared, over the years, to watch the castle come down.