A reader directed us today to a tweet by one of the most consistently abusive Tory trolls on social media, slightly concerned about whether his gleeful assertion of a 12% drop in SNP support had any grain of truth to it.

If you’re in a hurry, the short answer is “No”.

It’s possible to make the claim, of course, because different polling companies produce different ranges of results. The only way to find out what’s really happening in a way that actually tells you anything about which way public opinion is moving is to compare apples with apples – that is, to measure the changes within polls conducted by the same pollster.

So we did that. We charted, with the help of What Scotland Thinks, each company’s findings over the past 12 months, or as near as it was possible to get.

These are the results.

YOUGOV (CONSTITUENCY)

12-month change: SNP -1, Lab -4, Con +4, Lib -1, Others +2

YOUGOV (REGION)

12-month change: SNP +3, Lab -6, Con +3, Lib -1, Grn +1, UKIP +1, Others 0

SURVATION (CONSTITUENCY)

12-month change: SNP 0, Lab -2, Con +4, Lib +1, Others -3

SURVATION (REGION)

11-month change: SNP -1, Lab -2, Con +5, Lib +1, Grn -1, UKIP -1, Others -1

TNS (CONSTITUENCY)

11-month change: SNP -4, Lab 0, Con 0, Lib +3, Others +1

TNS (REGION)

11-month change: SNP -3, Lab +2, Con +1, Lib +1, Grn -2, UKIP -1, Others +1

IPSOS MORI (CONSTITUENCY)

8-month change: SNP -2, Lab 0, Con +4, Lib -1, Others -1

IPSOS MORI (REGION)

8-month change: SNP -4, Lab -2, Con +2, Lib +1, Grn +2, UKIP +1, Others -1

PANELBASE (CONSTITUENCY)

9-month change: SNP -3, Lab -1, Con +2, Lib +1, Others +1

PANELBASE (REGION)

9-month change: SNP 0, Lab -2, Con +2, Lib +2, Grn -1, UKIP 0, Others 0

And that’s that. What the polls show, when analysed in any meaningful like-for-like context, is that the last year of campaigning has basically achieved nothing. Almost every change figure in the tables above is within the 3% standard margin of error for polling, which suggests that in essence the polls haven’t moved at all.

Some show the SNP slightly up, some slightly down and some static. The same is true for all the other parties, except that no poll has showed the Tories losing support since a year ago. If you take averages of all the polls – just for fun, because the differing dates make it scientifically pretty worthless – the numbers come out to:

SNP -1.5%

Labour -1.7%

Conservatives +2.7

Lib Dem +0.7

Green -0.2%

UKIP 0

Others -0.1%

That, readers, is a whole lot of not very much going on.

(It strikes us a bit like the old routine by, we think, top US comedian Rich Hall about how Coke and Pepsi spend billions of dollars every year on competing advertising that changes nobody’s opinion, to the point where if someone asks for a Coke in a pub and the barman says “We’ve only got Pepsi, is that okay?” the response is a bemused shrug of total indifference.)

Labour have lost the most ground and the Tories gained the most, but every average is within the margin of error. Even if the figures were to be accurate, Labour would still hang on for a close but clear second above the Ruth Davidson No Surrender To The SNP Anti-Referendum Party (as we believe the Tories will appear on the ballot paper).

So it looks as if the biggest uncertainty about next month’s election is whether the Lib Dems will fight off the Greens for fourth place. (We suspect they will – although the Greens are ahead in more polls they contest only a couple of constituencies and their support is more geographically polarised – but it’s definitely up for grabs.)

A relentless 12-month bombardment of “SNP BAD!” from the media and opposition has simply bounced right off the hull of Nicola Sturgeon’s battleship, leaving barely a scratch, and no amount of desperate spin can conceal that fact.