Anyone who disappeared to foreign climes at the start of half-term last weekend might be forgiven for thinking they’ve arrived back in a different country.

This time last week, the Conservatives and Labour parties were busy warbling their way through a No pasaran type ditty in relation to the constitutional debate. This far and no further, or to quote the Scottish Conservative leader, Ruth Davidson MSP, the Scotland bill (which may or may not still be wending its way through Westminster) represents a “line in the sand”. The inference is, of course, that the Tories are not prepared to devolve anything more to Scotland than what is already in that bill.

Indeed, last weekend, we were still labouring under the misapprehension that Ms Davidson and her Scottish Labour counterpart, Johann Lamont MSP, were leading the constitutional debate for their respective parties.

That was until Mr Cameron ventured North and delivered a speech which has fair set the heather alight. Suddenly, the debate has been turned on its head. Suddenly, the Prime Minister is prepared to consider giving as yet undefined and unstated powers to Scotland, continuing the process of devolution. Assembled hacks gasped and gushed.

And now, former Chancellor of the Exchequer, Alistair Darling MP, has suggested that Scotland should become responsible for raising money as well as spending it. Apparently, without his tongue in his cheek, Mr Darling reckoned devolving income tax would be pretty easy to do. Now that he wants it to happen of course; it was a different story, oh about a fortnight ago.

They might deny it, but this smacks of a pincer movement, orchestrated and apparently being led at UK level. Which washes the Scottish leaders up on a beach some way beyond the line in the sand that was previously drawn. I’m sure they’re wondering, like the rest of us, what kind of freak wave it was that caused them to land there.

It’s good that the debate has shifted so far and so quickly. For one thing, the Unionist parties have woken up to the fact that the Scottish people want more, much more than they were initially offering. Moreover, given the tenor and tone of Cameron’s speech and of the interventions Alistair Darling has made in recent months on a range of issues, at last, we have sparring partners who might give the First Minister a run for his money.

But where does that leave the Scottish Conservative and Labour leaders? Putatively in charge of anti-independence campaigns for their own parties but facing the prospect of marauding alpha males marking their territory whenever the fancy takes them. That’s not a good place to be and both parties’ Spring conferences will now be much more interesting as a result.

Of course, nice speeches and interviews promising jam tomorrow are all very well but they’re not likely to carry the day. According to those nice men from the Union, we can have more control over some things in our life but not just yet. Not until we vote no to independence, then they’ll be more than happy to have a think about it and give us some more powers.

Problem is, can we trust them? After all, they’ve got form. Some of us have long enough memories to remember empty promises before. And even if we don’t, well every journalist in the land has filled in the gaps for us in the last few days. 1979, Lord Home. Vote against home rule and we’ll give you something better. Pah.

In any event, if this lot really meant it, couldn’t they have done it before now? After all, Scottish people have been indicating for a few years that they’d like more please. To some extent, it’s ancient history. We are where we are, this week at least. Which is pretty confusing for some. Not least the SNP.

This time last week, they were the ones on the front foot. Pushing against the intransigence of the coalition UK Government on procedural matters, subtly (and at times, not so subtly) hinting that “they” were being anti-Scottish, refusing to allow “us” to have this debate and referendum on “our” terms. But in the topsy-turvy world we now appear to inhabit, that has changed. What, after all, is anti-Scottish about offering the people what it is they say they want? We’re listening to you is the message, “we’re” the ones who can deliver what you want, not “them”. Suddenly, who is “us” and “them” is not quite so clear.

And here’s another neat twist. For weeks now, the SNP has been bombarded with questions from all quarters. Tell us about independence they cry, what does it mean? Will we still be able to buy stuff? Will they let us in or throw us out of Europe? Will there still be an army? What about Queenie? Some of us actually want to know about more prosaic, everyday stuff, that, like, matters, but we’ll pass on that for now.

But doesn’t it sound familiar? Who did we hear asking for some detail all of a sudden? Ah yes, that would be the First Minister. It’s not good enough to proffer more devolution without spelling out what that consists of. And he managed to utter this with absolutely no hint of irony whatsoever.

See? Who’d have thought that in a few short days, we would have travelled up and down and all around in the debate. But at least, we do now have a debate. The status quo is no longer what it was. The choice – when we get there – is undoubtedly going to be between some level of increased devolution and independence.

Devo plus, devo max, indie lite, full fat indy. These are the options before us: all we need to know now is what any of them actually means.