TOM Nairn, Scotland’s greatest political philosopher of the modern era and doughty champion of independence, has left us at the age of 90. He was a kindly, thoughtful individual whom I was privileged to call my friend for half-a-century.

Like Stephen Maxwell, the national movement’s other towering intellect, Tom will not see the sunrise when Scotland recovers her ancient statehood. But in some misty Valhalla, he and Maxwell and Hamish Henderson and Hugh MacDiarmid and other pioneers of the struggle will be looking on. And, of course, arguing vociferously with each other. For as Tom would heartily testify, Scotland is an idea, an argument, an adventure and forever unfinished.

In the next few weeks there will be many obituaries of Tom Nairn, a son of Fife born in 1932. For the uninitiated, he was a political thinker with a global reputation; a writer with a magnificent, poetic turn of phrase; a restless thinker who always challenged intellectual and political convention; and a resolute internationalist in the best Scottish tradition.

He was inspired by Marx and one of the first people in the anglophone world (along with the poet and folklorist Henderson) to discover the radical ideas of Antonio Gramsci on how culture and ideology are mobilised to defend the establishment status quo.

Tom had a Scottish Enlightenment appreciation of ideas and their power to shape the world if only mobilised for political action. He was the son of a dominie and so one of those “organic” intellectuals – close to the people rather than the elite – described by Gramsci as necessary to invent a new way of seeing the world that would allow the oppressed and dispossessed to overthrow the existing order.

Tom would fulfil that calling in his 1977 magnum opus The Break-Up of Britain, a book that inspired my generation of post-1968 activists and made us understand the necessity to combine the struggle for socialism with the fight for Scottish independence.

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I once had an argument on a public stage with a tedious Unionist intellectual – it was during the 2014 referendum campaign – who was busily explaining to the audience that Tom Nairn’s book was an intellectual failure that deserved to be forgotten.

Because, of course, Britain had not broken up and so Nairn had proved a false prophet and an intellectual lightweight. However, Tom never pretended he could predict the day or the hour when Scotland would shatter the bonds of the archaic, reactionary British state.

What he did do – magnificently – was to present a cogent argument, some half-century ago, that the national and identity questions would continue to dominate and define British politics forever afterwards, until that ramshackle state fell apart. And so it has come to pass.

But Tom’s thought and analysis had a wider intellectual and historic remit. He was first and foremost a philosopher, from a land where philosophy and theory are still prized – in opposition to the worship of empiricism found in English academic circles, and certainly in English politics.

Tom was influenced by Marx – the young, philosophical Marx who eschewed the alienation of mankind under capitalism. Tom first turned his ferocious intellect towards deconstructing and defenestrating the British Labour Party.

This was when Harold Wilson was Prime Minister in the 1960s. Tom saw feeble, cringing Labourism as the principal ideological mechanism that kept the working classes subordinate to the British ruling caste.

Later, in his brilliantly original book The Enchanted Glass (1988), Tom extended his analysis of the ideological prison that is British society to encompass the monarchy and the fetish made of the appalling Windsor family.

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Not content with a simple denunciation of monarchism, Nairn attempted (for the first time on the left) to understand the hold that royalty has over the British imagination.

This cultural hold provides much of the ideological underpinning for the British prison of nations. Even if The Enchanted Glass is not wholly successful, it still shows Nairn’s constant ability to chart new intellectual and political territory.

However, the restless iconoclast in Tom Nairn upset the left as well as the right. In 1973, he wrote The Left Against Europe which denounced the British left-wing for its anti-European stance.

While critical of the then Common Market as pro-big business, Nairn argued we should not oppose British entry because it provided a wider, less chauvinist platform for uniting workers’ struggles across the continent.

In defending a narrow British sovereignty, the left was imprisoning itself in Little England mentality and re-inforcing the ideological hold of a reactionary British nationalism. Many on the left never forgave Tom for this critique, perhaps because they had no riposte.

Tom paid for his iconoclasm and intellectual independence. He was denied the academic posts he richly deserved and so led a peripatetic life lecturing where he could. He eventually found a permanent teaching post in Australia, an exile from his homeland like many before him.

But as the national movement in Scotland morphed from cultural maverick to dominant political current, Tom’s seminal intellectual contribution was finally recognised.

Not that Tom was an armchair warrior. In the heady days of 1968 he was fired from Hornsey College of Art in London for supporting a student occupation. In 1976 he was a member (like me) of Jim Sillars’s short-lived Scottish Labour Party.

In the early 1980s, Tom and I launched The Bulletin of Scottish Politics, in an attempt to inject some intellectual rigour into local political debate, in the aftermath of the abortive 1979 devolution referendum. Alas the times were not efficacious and the journal folded after a few issues.

In his later years, Tom returned to Scotland and found personal happiness and intellectual respect. But he continued to explore ideas. In the last literary debate I had with him, he chided me for being pessimistic about the progress of the national movement.

He was right. For as he explained in The Break-Up of Britain, the centrality of the national question does not rest on the episodic performance of individual politicians or political parties.

Rather, it is located in the structural crisis of the arthritic British state itself. And until that elitist, moribund state entity falls apart, every one of us is stuck in the political limbo Tom Nairn predicted back in 1977.

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This crisis of the British state is terminal. Worse, the stasis of the British state has led to permanent economic decline. Average, per capital household income in Britain has been flat for the last 15 years.

Productivity stubbornly refuses to increase. Meanwhile, the media are obsessed by the rantings of a former princeling and what stockings Charles Windsor will wear at his coronation. Tom would say: “I told you so.”

It is always hard to say goodbye to an old friend. But Tom Nairn leaves left behind some of the most illuminating political writings of the past 50 years, to help guide us. He was an extraordinary modest and self-effacing man. He also had a dry, withering sense of humour.

We are a small nation and can ill afford to lose our best and brightest. But Scotland is uniquely a nation rooted in its literature and philosophy. In the Pantheon of Scottish writers and philosophers, Tom Nairn now takes his rightful place.