SPARE a thought this weekend for the Labour MP for Glasgow North East, Willie Bain. Opinion polls had suggested he might soon be the only Labour MP left in Scotland.

It could have made him a shoo-in for Scottish Secretary. Then, on Wednesday, disaster struck. A poll from Ipsos Mori suggested that the SNP would take every seat in Scotland. Poor Willie Bain's brilliant career was cut tragically short.

Of course, no-one believes these polls. I can't see the SNP winning every seat in Scotland. Even after catastrophes, some people are left standing and I

fully expect that on Friday morning there will still be a number of Labour MPs boasting that they survived the Nat-aclysm.

But no-one can be in any doubt that a fundamental change has taken place in the fabric of Scottish politics. It seems almost unbelievable that only five years ago, Labour won 41 seats in the 2010 General Election against the SNP's six. This General Election will almost certainly mark the end of Labour's long electoral dominance of Scotland.

The votes have yet to be cast, but already Labour are in mourning this weekend. Writers like Stephen Daisley, the STV political blogger, have been penning elegies to the party of their grandfathers. "If we are to break our ties to Labour," Daisley wrote in the Daily Record under a picture of his grandad, "they are due a debt of gratitude for what they bequeathed us - a free and democratic country, a welfare state, and universal healthcare."

That is undeniable, though the problem most Scottish voters have is that they can no longer recognise that Labour Party. The SNP's Nicola Sturgeon seems a more convincing advocate of those social democratic virtues than Labour - certainly at a UK level. We'll come to Scottish Labour in a moment.

For this is, of course, a UK General Election not, as it sometimes appears, a repeat of the independence referendum. The First Minister of Scotland has emerged in interview and debate as one of the leading voices on the contemporary British left. It is Nicola Sturgeon who has argued against austerity and for annual increases in spending against the Conservative cuts or Labour's "balancing the books". The IFS may quibble about the austerity timetable, but I have yet to hear Ed Balls endorse her commitment to invest some £180 billion over five years.

She has condemned the creeping privatisation of the National Health Service in a way Labour cannot because, as Labour's health spokesman Andy Burnham has admitted, it was under their watch that the market reforms were extended to allow the wholesale invasion of private providers into the NHS. (In office, the SNP eliminated the last vestiges of private provision within the NHS when it merged the privately operated treatment centre at Strathcathro in Angus into the NHS in 2008.)

Sturgeon has argued unequivocally for universalism in areas like higher education. Universalism was one of those great "grandad" principles of the original welfare state. Somehow it got lost as Labour turned to means-testing and "targeted benefits".

British voters have seen a new theatre of politics during this campaign. The three-men-in-suits monopoly has been broken by articulate and radical women politicians talking a different kind of politics. But the strongest voice in the TV debates has been that of the First Minister of Scotland. And the voters rather like it. Nicola Sturgeon has emerged in last week's Herald TNS poll as the most popular leader - not just in Scotland but in the UK.

But to her credit, Sturgeon has not simply confined her radicalism to the safety zone of gender equality. The policies she has been advocating are ones that have been considered beyond the pale in Westminster for nearly three decades. When did you last hear a major UK political leader arguing consistently in an election campaign for unilateral nuclear disarmament - and getting a hearing?

Nicola Sturgeon has been the only party leader consistently and even passionately to defend the contribution made to the British economy by immigrants. For her efforts, the conservative press has been styling her as the new Tony Benn, a modern advocate of 1970s loony leftism. She is "the most dangerous woman in Britain" who would "leave Britain defenceless",

allow open borders and unleash a "ruinous £180bn debt-fuelled spending spree".

It may be that the real achievement of the "wee lassie" in this election has not just been piling up votes for the SNP, but placing radical ideas back on the UK political agenda.

However, Ed Miliband refuses to have anything to do with them. In the final TV debate he laid it on the line: he will not do any deals around "Trident or the deficit" with the SNP. The Labour leader said he would rather see a Tory government installed in Westminster than form a progressive alliance with Nicola Sturgeon.

That must have broken more than a few hearts in Scotland - and in England. How many ordinary Labour voters would prefer a Tory government to a deal with a party, the SNP, that calls for the mansion tax, increased minimum wage, rent controls and many other cherished policies?

Ed Miliband tried to give the Scottish voters an offer they couldn't refuse: vote Labour or get Tory. But the way things are going it looks like they will call his bluff and vote SNP to ensure that Scotland's progressive voice is heard in Westminster.

Of course, to many Labour nostalgics the SNP's progressive postures are phoney. They have convinced themselves that the SNP are not really social democrats at all but clever shape-shifters. As Stephen Daisley puts it: "[The SNP] have secured the support of much of the Scottish left without once venturing beyond the low-tax, pro-business, neo-liberal centre ground".

Among most Scottish journalists this proposition is seen as self-evident. The SNP's policies on tuition fees, NHS privatisation, gender equality, prescription charges, 50p tax etc are seen as social democratic window-dressing. But sometimes, just sometimes, what you see is what you get.

At any rate, Scottish voters no longer seem willing to be guided by the cynical priests of the Unionist consensus. Politics is always about the triumph of hope over experience. It is that daft counter-factual proposition that politicians might actually do in office what they say in election campaigns.

But in the Scottish Parliament after 2007, the SNP at least made a convincing attempt. And the voters rewarded them for that with a landslide victory in 2011. The Labour establishment and their media supporters never forgave the voters for it. What is happening now is that faith in the possibility of change is being translated to Westminster.

The Scottish voters are tired of being told that it is somehow indecent to support a nationalist party, even though it seems more socialist than anything else on offer. They are fed up being scolded by authority figures for abandoning the poor an dispossessed of northern England, as if they are in some way responsible for Westminster policies since Thatcherism.

Above all they are tired of being told that they should unthinkingly support a Labour Party which has for many years been a hollow shell in Scotland, and in England a playground for special interests and commercial lobby groups.

But enough of this lamentation for lost Labour. There is something much more important happening in Scotland than the eclipse of a political party that is past its sell-by date. Something more important even than the rediscovery of social democratic values in a new context.

Travelling and speaking all over Scotland in the past couple of months I have been struck once again by an irrepressible sense of excitement and self-confidence. The civic engagement that fuelled the referendum campaign and motivated 97% of Scots to register to vote is still there.

People are still coming out in their thousands all over Scotland to talk politics in pubs, town halls, theatres and book festivals. I've spoken to many of them myself and it is difficult not to be infected with their enthusiasm. Armed with the internet, seized by a sense of communal purpose, the people of Scotland refuse to believe that a better society is impossible.

Scots are having fun too. They have taken to politics in the way people used to follow football. There is something of the Tartan Army in the legions of SNP followers on the internet, only a lot less male-dominated.

Again, the voices of sobriety and conservatism warn against this outburst of civic positivity as if it were some dangerous lapse into emotional irrationalism. "Scots have simply gone mad," say the columnists. But what a miserable, misanthropic, reactionary attitude that is.

This is no more irrational than the optimism that led to the Chartist demonstrations in the 19th century; that drove the Suffragettes; that led to the 1945 Labour landslide and the welfare state. These movements were all dismissed as borne of irrationality and unreason. The Establishment always rings the alarm when the people start to take history into their own hands.

They were told after the referendum result that they had to get back in their box and stop this dangerous festival of democracy. You've had your fun. But the people didn't go back in their box. They looked around themselves, found that the world hadn't come to an end after a No vote, and went right on keeping on.

Unfortunately, there emerged no continuing political expression of the Yes campaign, no Yes alliance. So the people decided that if they couldn't make a new party they would remake an old one. The SNP's membership has risen 400% since September 2014

People wonder where Nicola Sturgeon's extraordinary poise and purpose comes from - so memorably depicted in that picture of her walking the bar in the gymnasium after launching the party youth manifesto. It's not some magic personal quality.

Nicola Sturgeon is a very capable and intelligent politician, but no-one could fail to recognise the transformation in this working-class woman from Dreghorn since she became leader. Sturgeon has become the personification of this civic renewal movement that has been sweeping Scotland. She speaks with confidence about her party's commitment to progressive change because she believes it.

But she also knows that she is leading hundreds of thousands of Scottish voters who refuse to give up on the possibility of change; who will not lapse back into the apathy-and-retail politics that is handed to them by the press and the Westminster Establishment.

And this is not so different really from the solidarity of the old Labour movement. It is the same progressive politics translated into a post-industrial age. You have the same enthusiasm for debate and argument; for self-education and street politics.

But contrast this with the relentlessly dry and negative discourse of the Scottish Labour Party today. What has it had to say in this election? Fiscal autonomy will bankrupt Scotland; Sturgeon is planning another referendum; and the largest party gets to form the government. The last two are simply wrong.

Sturgeon has said repeatedly that even if she wins every seat in Scotland it will not be a mandate for another referendum. Only a "material change" such as the UK referendum on Europe, could trigger another referendum in the next decade. In Westminster, it is the party that commands a majority of votes in the House of Commons gets to be the government, not the largest party.

Labour thought that full fiscal autonomy (FFA) was an election-winner after the IFS forecast that Scotland would have a deficit if it controlled all its taxation. They hammered Nicola Sturgeon relentlessly on her plans for "full fiscal austerity".

However, Scottish voters realised that FFA is not going to happen because the big Westminster parties would never vote for it. What will happen are Labour-supported Smith reforms devolving income tax, which already sounds like a form of fiscal autonomy

But the worst thing about the FFA "bombshell" as Labour depicted it, following the Tories' tax bombshell of the 1990s, is that it is simply another statistical way of saying Scots are incapable of running their own affairs. Too wee, too poor etc.

These negative messages occluded Labour's positive pledges. The £1600 grants for non-studying 18-year-olds, increased minimum wage, anti-poverty fund and so on got lost in the obsession with portraying the SNP as closet Conservatives. Labour's campaign turned into one big whinge against the Nats.

Even before the polls open, Labour MPs have been saying that Jim Murphy is to blame for Labour's problems in Scotland. He isn't. Murphy is a capable politician on the wrong side of history.

In the past, his barracking and shouty style might have been seen as passionate and committed. He is one of the most resilient politicians I have ever seen, capable of spending all day being shouted at in the streets and still appearing to sound positive in the TV studios.

But Nelson Mandela himself could not have turned around Labour's fortunes in these few short months. We are seeing a political sea change, a generational transformation and a national awakening all at the same time. In this election, unlike any before, it's all about Scotland.