By now, Gordon Brown must have staged more interventions than a celebrity psychiatrist. Whether the patients are responsive is, obviously, another matter. The man with the cure for whatever ails you doesn’t give up easily.

Quite what Jeremy Corbyn makes of it is a matter for study. We can assume that Labour’s new leader was not informed about another imminent eruption on Mount Broon. We can further assume that neither he nor his predecessor-but-one was even slightly bothered by the fact.

What does Mr Corbyn think about Scottish matters? All we have to go on is the faintly puerile idea that Team Jez would have us “come home” to wherever the party happens to reside. This is tacked to the claim that Mr Corbyn is the answer, whatever the question happens to be. It’s not what you’d call a comprehensive policy.

It falls to the godfather of new Labour, then, to take responsibility. Not, presumably, for the General Election results – les evenements de Mai, as the party refuses to call them – but for shepherding us towards a situation “as near to a federal arrangement in the UK as you can be in a country where one nation is 85 per cent of the population”.

As interventions go, this is devolution in action. Regardless of whether Mr Corbyn has anything useful to offer, the canton of Gord has exercised autonomy, with a Glasgow University audience for witnesses, and self-determined another solution for Labour’s Scottish – and British – problems. How now, as you might say, Brown vow?

Not so good, it transpires. One paraphrase of the former Prime Minister’s Glasgow speech is that he and Labour did a deal with the Tories and the Tories have ratted. You could call that careless on Mr Brown’s part. You could even call it a metaphor for everything the Better Together palaver came to signify for Labour in Scotland.

That would be “betrayal and a near-wipeout”. You don’t boast about such things. Nor, arguably, do you complain after the fact that your supping-with-the-Devil spoon had a hole in it. For his own part, Mr Brown kept Better Together and the Conservatives at bargepole distance during the referendum campaign. If the consequences have been as he describes, he might wonder why he didn’t do more to save his party from its enthusiasm for Tory funding.

Never mind. We are, as political folk like to say, where we are. According to Mr Brown’s remarks in Glasgow, we are in fact at the edge of “a perfect storm – an explosive cocktail of measures that could blow the Union apart”. Omissions from the Scotland Bill, particularly over welfare powers, mean that the Conservative Government is “defying” the Smith Commission. Mr Brown also alleges that London will retain a veto over some of Holyrood’s decisions.

Clearly, Labour’s former leader takes all of this personally. The "vow" that added a fetchingly wrinkled look to the front page of the Daily Record, a “historic joint promise” two days before the referendum, was a wrinkle he helped to devise. The claim that we had been set on the road to near-federalism was his. The pledge to every voter that Smith would be enacted in each particular was born of his involvement. It is an issue, if you have a weakness for these things, of trust.

One way or another, Labour in Scotland has had a lot riding on the delivery of those “welfare top-up powers”. Quite what they involve is not exactly clear. Quite where Mr Brown’s logic takes us might not yet be obvious to him or his party. In one respect, though, the matter is simple.

David Cameron insists that everything agreed by the Smith Commission – “Every single thing Lord Smith represented in terms of welfare” – is being delivered by the Scotland Bill. David Mundell, the Scottish Secretary, says there is no veto. Mr Brown says these claims are false.

By no coincidence, the Scottish National Party will now say “told you so” at length. Equally, if Labour’s erstwhile leader is right and we are witnessing a “double betrayal” liable to “blow the Union apart”, the SNP will manage to choke back the tears. Mr Brown is simply describing what Nationalists predicted from the start, with consequences foretold and welcomed. Doesn’t he know that?

It’s an interesting question. Mr Brown has invoked risks that are, for a Unionist, supremely dangerous. You could almost believe he is confident that there will be a last minute change of heart from the Government. After all, if it doesn’t happen the blowing apart can commence. The SNP will have been right and the Union will be lost. But could Mr Cameron really turn around now and say, in effect, “Forget all that stuff about Smith-in-full. There are a couple of tiny omissions”?

In other words, if Mr Brown fails to get his way he will have made a large part of the SNP case. The "vow" will have been exposed, finally, as a con by a former leader of the party that let itself be suckered (as Nationalists will say) into Better Together, a figure who now sees the dissolution of the Union as the inevitable conclusion of a miserable “double betrayal”.

Even if Mr Cameron decides to throw an old adversary a rope, Labour in Scotland isn’t exactly home and dry. Back in February, Mr Brown and the leader formerly known as Jim Murphy put it about that the Smith recommendation for Holyrood to gain “new powers to create new benefits in areas of devolved responsibility” could be extended by Labour.

In a speech in Edinburgh, with Mr Brown at his side, Mr Murphy talked of this “vow plus” as ensuring “that the Scottish Parliament has the power to create new benefits, in addition to the guarantees of the UK benefits and pensions system”. Ian Murray, shadow Scottish secretary, has since tried to amend the Scotland Bill to ensure that Holyrood “has the unrestricted power to create new devolved benefits” in addition to the UK system.

In Glasgow, Mr Brown talked about the promise of “clear and unambiguous right to top-up welfare benefits”. Is he talking just about short-term, lump-sum discretionary payments (the usual meaning of top-up)? Is he calling for Mr Murray’s “new devolved benefits” in addition to that? Something in between? Since the former Prime Minister is demanding the powers to give Scotland’s poorest people a defence against the depredations of the old Better Together partners, clarity would help.

But wait just a second. Isn’t a unified welfare state a bedrock of the Union Mr Brown defends? Isn’t the fact that Tories are often in government a price Scotland pays for the advertised benefits of the Union? If he demands “the very powers that are needed to counteract welfare cuts and the austerity they bring” why, why in logic, stop there?

The Union promoted by Better Together and Mr Brown’s party has turned out to mean a Tory government laying waste to the welfare state. Such is the carnage, he thinks we’d be better off managing human need in our own way and on our own terms. And still he leaves the question: why stop there?