Image copyright Getty Images Image caption Is Nicola Sturgeon set to smash her opponents in the Holyrood election?

Door-knocking in an election campaign in the dark when it's cold and wet is never fun. For Labour canvassers in Scotland on these long winter nights, it's often torture.

They know that victory in the Scottish Parliament poll on 5 May is only a remote possibility, and that the likely outcome is an even bigger majority for the SNP which could then look forward to being in government until 2020, completing 13 years in power in Edinburgh - more than half the lifetime of the Scottish Parliament.

No-one could argue against the significance of that: if they win again in May, the nationalists will be the natural party of government in Scotland.

"Labour could'nae run a bath," I heard one voter telling an SNP canvasser on the south side of Glasgow last week, and it caught the mood.

There's no sign, in the polls or on the doorsteps, of Labour escaping the humiliation that was visited on them in the general election last year, when they won a solitary seat.

At first glance, it is a puzzle. Nicola Sturgeon's government has to defend a record - on education, aspects of the NHS, police reform - that gives openings for a good opposition.

But Labour at Holyrood has been weak. And in the country, although you hear plenty muttering about the SNP and dark talk of a "one party state", the truth is that the nationalists are still seen as broadly competent and - when you put the independence question aside - remarkably non-ideological.

And in case of doubt, their campaigners are quick to point out to any sceptical voter that the May election has nothing to do with the question that was settled (for now) in the 2014 referendum. This is about day-to-day government.

Image copyright PA Image caption Kezia Dugdale does not seem to have received a lift from Jeremy Corbyn's election

Labour, split by the referendum when many of their traditional voters said Yes to independence and then crushed in the general election, are only a wobbly opposition, not a government-in-waiting.

And anyone who thought that Jeremy Corbyn's election would help the chances of Kezia Dugdale, the Scottish leader, who is of a different stripe anyway, won't find any evidence for it on the streets.

Indeed, Ruth Davidson, the feisty Conservative leader, is bullish enough to toy with the thought that her party (with 15 out of 128 seats in the current parliament) might overtake Labour (38).

Scottish Parliament: Current state of the parties:

Scottish National Party: 64 MSPs

Scottish Labour: 38

Scottish Conservative and Unionist Party: 15

Scottish Liberal Democrats: 5

Scottish Green Party: 2

Independent: 3

No Party Affiliation: 1

Who will be the opposition?

This is fairly fanciful stuff, but it's a measure of the mood. The question many people are asking in this campaign isn't who will win, but what kind of opposition there will be.

One voter we heard last week told SNP canvassers that she wasn't interested in politics, she just always voted Labour. But two words interested her. "Nicola Sturgeon." It turned out she liked her, and might change her mind.

Image copyright Getty Images Image caption Ruth Davidson is hoping the Conservatives can recover lost ground

I have lost count of the people who have asked me in the last few weeks when the shine will start to come off the SNP. The answer is: not yet.

It is remarkable that a party can have four of its new MPs at Westminster facing serious allegations of wrongdoing and hardly miss a step, and in Edinburgh they power on.

Writing this in January, it seems rash to predict a result in May. Who knows what cataclysm might be lurking round the corner? But as things stand now, there will be another SNP government and Labour's agony in Scotland will continue.

Their efforts now are directed at avoiding one particular horror, a nightmare for them.

When the Scottish Parliament was established by the Blair government in 1999, the electoral system was designed, in part, to guarantee that it was unlikely that one party would dominate.

Half the seats would be elected first-past-the-post by constituency and the others on a regional party list by PR. That was meant to reassure Labour doubters that the SNP could never govern on their own.

Not only has that been confounded, but it is now possible - though still, on balance, unlikely - that Labour will fail to win any directly-elected seats, and will have to depend, like the Conservatives, on the PR vote to get seats at Holyrood.

The mood among Labour people is so low at this stage that avoiding that outcome would feel like a victory of sorts. How the mighty have fallen.