Pie chart by STV

A Westminster election poll for STV today gives the SNP a huge lead over Labour. Specifically, they're on 52%, with Scottish Labour on 23%, Scottish Conservatives 10%, Scottish Liberal Democrats 6%, Scottish Green Party 6%, Ukip 2% and 1% support for others.

With a uniform swing, they say that would give the SNP 54 out of Scotland's 59 MPs, with Labour getting 4 and the Lib Dems hanging on to one. Whilst various polls recently have looked pretty good for the SNP, this one shows a big shift in support.

STV say this poll, if replicated in May, would give the SNP 54 out of Scotland's 59 MPs. If Plaid Cymru hold onto their three (and I think they are looking good in another two seats on top of that), that puts the two parties together on 57 MPs: exactly the same number of seats that the Lib Dems currently have.

Scottish polls like this are generally quite soft. In England, there is a very small pool of people who will swing between the two biggest parties. Look at how voters in Scottish local elections, where candidates are ranked in order of preference, vote, and you find the opposite is true – the SNP and Labour rely largely on the same pool of voters, and they're pretty willing to switch between the two.

Scottish polls are also soft because people vote very differently in Holyrood and Westminster elections, but they don't necessarily think so hard about that differentiation when they are talking to the woman from Isos-Mori on the phone. At this point before the last Holyrood election – which took place only a year after the 2010 Westminster election, it always seemed to me that people were not really answering what they were being asked – how will you vote in Holyrood – but, rather, were saying how they had voted in 2010. Once the Holyrood election arrived, however, it was a different story.

That doesn't mean that this poll is wrong. People are very angry with Labour, and may well feel that they don't want them representing them in Westminster.

The poll in itself is also significant. The more that the media talk about how this election will be good for smaller parties, the better it will be for smaller parties. If the SNP break into the UK media narrative for this election, that will be excellent for them. This poll may well be enough to do just that. Likewise, if the SNP can plausibly say "we're better placed than Labour to beat the Tories here", then that'll potentially bring them a bucket load of tactical votes.

It's easy to focus on how this poll is about the melt-down in Labour. But it's also worth noting that it's the first I've seen since Sturgeon became de-facto SNP leader. For years now, unionists have vilified Salmond. The problem with this personalising strategy is that it means he's been able to walk away, take all of that flack with him, and reveal a relatively unsullied party to carry on the struggle.

It is clear, though, that this is in part because of the Labour melt-down - with the field work done over the weekend right after Lamont resigned. Each of the candidates for leader will have got a bit of a fright as the figures emerged today - but how it impacts on the result, we're yet to see.

In part, this is about the changing nature of Westminster elections in Scotland. If Scots see themselves as participating in the same way as people in the rest of the UK do, then Labour are likely to do well. But if Holyrood is really the locus of Scottish politics, and MPs are the delegates sent to do a particular job at a faraway parliament, the dynamic is very different.

It's worth noting that the Greens are up significantly in this poll as well – on 6%, meaning the pro-independence parties are on 58%. This makes the possibility of a Green MP in the context of a pact of some sort with the SNP are serious proposition.

UKIP are on 2%, despite their recent gains South of the border. It seems the referendum was bad for them.

I have been saying to Labour people in London for a while now that they might want to think about what they would offer the SNP in coalition negotiations. They never seemed to take the point seriously. I suspect now they might.

Part of what's happened here is that, as has often been discussed before, people have engaged in politics during the referendum. They have looked more closely at each party. This is the reaction to Labour when it's actually scrutinised. Whilst much of this crisis has been made in Scotland, Labour across the rest of the UK shouldn't imagine that they would fair any better under similar scrutiny.

The thing that some in the SNP and Plaid have said they will demand if they hold the balance of power, their condition for making Miliband Prime Minister, is the scrapping of Trident.

It seems that securing significant more powers for Holyrood (and the Welsh Assembly) - more than either Labour or the Tories would ever want to offer - will be an inevitable condition of any deal too. If Westminster thought it could kick such questions into the long grass, it might soon find it is in fact kicking itself in the crotch.

One poll is one poll is one poll. I tend to prefer the average of polls as a more reliable indicator of what's actually going on. But even if this one is 5% out, it's still mind blowing. But at the very least, lots of people will be waiting with baited breath to see what the next one says...

...that said, the longer term story is clear here. The referendum - and the conduct of the various parties during it, has significantly changed Scottish politics, possibly forever.