Scotland has always had a reputation for tempestuous disagreements – for fighting and flyting. Power, passion, tribalism and men staying in pubs for long hours drinking and insulting each other are long-standing notions.

Last Saturday I went to Glasgow Citizen’s Theatre to see David Hare’s The Absence of War set in the run-up to Neil Kinnock’s ill-fated campaign in the 1992 general election.

Watching it in the turmoil of the current election campaign, and on the day of the Daily Telegraph story that claimed “Sturgeon’s secret backing for Cameron”, it made for the older centre-left audience a lot of contemporary sense.

In the period since the early 1990s, mainstream UK politics have become even more stage-managed and choreographed. Two decades ago Kinnock’s Labour Party’s obsession with its opponents, the Tories and Tory-supporting press, ended up giving their enemies strength that became a self-fulfilling prophecy.

Fast forward to today – and Labour’s attitude to the SNP. Take the so-called Sturgeon memo in which Scottish First Minister Nicola Sturgeon allegedly “confessed that she’d rather see David Cameron remain as PM” – the opposite of all SNP public pronouncements.

Scottish Labour leader Jim Murphy and British Labour leader Ed Miliband couldn’t believe their luck. This played totally into their stereotype and age-old trope of the Nats as “tartan Tories”. Miliband described the story as “damning revelations” and was still doing so 24 hours after it broke, trying to squeeze political capital from it. By then, it had been categorically denied by Sturgeon, and by the French consul at the meeting where the comment was initially claimed to have happened.

“Nickileaks” – or “FrenchGate” – as it quickly became known, highlights the degree to which some people try to deny, delegitimise and stigmatise their political opponents. And how doing so destabilises their own judgement.

Part of Scottish nationalism believes in a black and white account of history and politics. There is a world of heroes (Alex Salmond) and villains; chief of which are the Labour Party and BBC, the latter an agency of state disinformation and propaganda. All unionists are perfidious and planning to do Scotland down. There is in this anger and indignation a huge element of seeing Scotland as a powerless victim of others, either external forces or domestic enemies.

Yet a fundamental problem in this is that British nationalism does not see itself in such terms. For example, unionists dispute that their credo is another name for what many see as British state nationalism.

Following the above episode, Fraser Nelson described what he termed “the uglier side of Scottish nationalism” and went further, arguing that “the problem with nationalisms as a creed is that it attracts, as its followers, an angry mob”.

Nelson was talking exclusively about Scottish nationalism and ignoring the problems and limitations of British nationalism: its racist, xenophobic and reactionary side, its arrogance even in its progressive version, and its bad history and politics.

As important is the lack of understanding of British nationalism as a nationalism and where it takes us. It does this by seeing any UK-wide nationalism in pantomime colours – of Daily Mail sensibilities and Glasgow Rangers football supporters – not related to moderate unionism. Moreover, majority nationalisms the world over (of which British is one) refuse to see themselves in such terms, while problematising minority nationalisms (Scots, Welsh).

This reduces this debate to one defined by the claim and counter-claim of two nationalisms – one Scottish and out, and one British and in denial. This diminishes political debate and reduces the possibilities for different voices talking. How can a social democracy of the union or independence or something in-between get a look in? And what of green or feminist voices which came to the fore in the independence referendum?

Limitations of the emerging politics of the indyref and after are illustrated by recent examples. At a “Changin Scotland” weekend in Ullapool a couple of weeks ago, there was limited comprehension by a prominent commentator of the term “indyref echo chamber” with them asking me, “what does this mean and where is it being used?” When I explained it was about people hearing what they wanted to and telling others what they wanted to hear, they got it.

At another event a respected journalist commented that they didn’t find the high profile pro-independence website “Wings over Scotland” problematic or, in any way as some detractors did, “sexist”. They asserted that “people just said that sort of thing”, ignoring the combative way that “men from the games industry talk”.

These comments illustrate a certain attitude in soft pro-independence opinion that can be seen amongst some of Scotland’s well-kept political commentators such as Iain Macwhirter, Joyce McMillan, Kevin McKenna and Ruth Wishart. It is a partial view of the world – centred on their generational disappointment with Labour and a new-found embrace of independence.

This position feels that Labour has betrayed its principles and lost its soul, and then takes at face value SNP claims about progressive credentials and a commitment to social justice. The first is explored in-depth; the second hardly ever, and instead taken in good faith.

Part of the pro-independence commentary is happy to buy into SNP rhetoric. Seldom if ever are the regressive redistributive consequences of no tuition fees, free care for the elderly and the council tax freeze investigated. Or that in 16 years of the Scottish Parliament – under Labour and the Lib Dems, then the SNP – no serious redistribution of income and wealth to those most disadvantaged has taken place. Why bother with such detail when you can embrace a comforting story about fairness and Scotland’s centre-left consensus?

This is an acute tension in Scottish politics. The Labour Party were the political establishment of the country for two generations. The SNP are fast becoming the new political establishment. And yet a large part of pro-independence opinion does not want to explore this or hold to account the SNP’s progressive aspirations. Far easier to trot out the old story of lambasting Labour and how they have let down working people.

This mindset taps into Scottish historic traditions of believing in one dominant political and cultural story: from the Kirk to nineteenth-century Liberals, late twentieth-century Labour and now twenty-first century Scottish Nationalists. It is part of an elite independence of the mind that reinforces part of a popular mood. It isn’t an accident that one of the most resonant “Yes Scotland” posters was the one which promised “to end Tory rule forever”.

There are similar problems in strands of Britain’s political elites and in particular the centre-left Guardian-Labour version of Britain. It isn’t surprising that it has found it difficult to adjust to the rise of the SNP and Scottish nationalism and emergence of a fractured, fragmented UK politics.

As modern societies become more complex, diverse and divided and the old ideologies fade and fail to adapt, part of political discourse clings to new found assertions of certainty and in places zealotry. This can be seen in the rise of Ukip, anti-immigration, anti-welfare and Islamophobic sentiment. The SNP present a very different, more grown-up politics than Ukip, but part of Scottish nationalism has a similar simplistic rejection of parts of the modern world.

The Scottish debate of recent years – of a growing self-government, political autonomy and cultural confidence has been refreshing, progressive and a positive contribution to life north of the border and these isles. That makes it more important that the limits of a debate dominated by the mutual claims of two nationalisms, Scottish and British, is seen and challenged.

Both Scottish independence, as an end in itself, and the defence of the union –irrespective of the values and record of that entity – are political cul-de-sacs for radicals and progressives. The Scottish debate needs to mature, and develop an even more distinctive third space that is unashamedly centre-left, social democratic – and outward-looking first and foremost.

This would entail people in the SNP, Labour, Greens and Lib Dems, and those of no party, challenging not just the old orthodoxies of Labour Scotland, but the new ones of the SNP era.

Scottish politics for all the hope, energy and optimism of the indyref has for too long been shaped by mantras of Thatcher, Blair, the poll tax and Iraq. These mattered in the past but now it is more urgent than ever to throw off the shackles of what in a different context Jarvis Cocker called (talking about the continued obsession with the 1960s) “the children of the echo”. Scotland’s children of the echo have for too long told us that everything will be all right if we just don’t vote Tory and believe in our comforting myths. This is a moment to begin a more open and challenging conversation.

Gerry Hassan is author of “Caledonian Dreaming: The Quest for a Different Scotland” and the recently published “Independence of the Scottish Mind”.