One could hear those infamous tectonic plates shifting as the bow-tied Gordon Brown addressed Scotland's captains of industry in Glasgow last night.

The particular landscape, which was moving, was that of the Scottish Parliament and whether or not it should have more powers.

The first rumble occurred back in November when Wendy Alexander spoke for the first time about Labour looking at the "housekeeping bills" of Holyrood. She told a television audience how there was a "desire in Scotland to walk taller than to walk out" of the Union. She insisted how she was not an "unthinking Unionist" and that there were "issues to be resolved".

Now at the time the view from London was that dear old Wendy was "barking" - to use one senior Labour figure's colourful description of the then leader of the Labour Group in Edinburgh.

Indeed, there appeared to be a general consensus among the Westminster Labour clan that some of their cousins at Holyrood had lost the plot and that to concede more powers to the Scottish Parliament would be simply "playing to the SNP tune".

The thinking in London was that once you begin to feed the devolution beast with its insatiable appetite, there was going to be only one inevitable conclusion.

So in December, it came as no surprise when the PM was asked about the issue and appeared to knock the whole thing firmly on the head by declaring: "Sometimes people have forgotten this is devolution, this is not a form of federalism." In other words, those who want more powers for Holyrood can whistle.

In January at his monthly press conference, Mr B was asked directly if he was for or against Holyrood having more tax powers. He dodged the question, saying only that the debate about "accountability for money spent" had to be begun, noting without explanation how 2008 would be an "important year for the Union".

Again, it was regarded as something of a slapdown for Ms Alexander given the absence of direct or even indirect support for her idea. But looking back, had Gordy had a Christmas epiphany on the subject? Given that all the polls north of the Border were saying the same thing - most people do not want an independent Scotland but do want Holyrood to have more powers.

A few weeks later up popped David Cairns, the thoughtful cookie at the Scotland Office, who openly spelled out what, at the time, was thought to be No 10's settled view. "The Government's position is that the current fiscal arrangements benefit Scotland, that there are stable, transparent increases in public spending in Scotland. There is no case for the massive restructuring of that. In any case," noted the MP for Inverclyde, "the Scottish Parliament has powers to levy additional taxes if they think that's what they need and they haven't used them."

In an exclusive interview with The Herald, he added that talk of extra tax-raising powers for Holyrood was a navel-gazing exercise for the "McChattering classes" and what the UK Government and Labour should be focused on was how to help hard-working families cope with their everyday lives - education, health, money, tackling crime, etc.

Yet a week later, the PM appeared on the BBC to declare that no one should prejudge the Calman Commission and then, significantly, he pointed out how "in any other devolved administration in the world" financial responsibility not only involved spending money but also how to raise it. He even referred to raising money through "assigned taxation" ie taxes raised in Scotland, spent in Scotland. The ground was rumbling and seemed to be moving significantly Wendywards.

Fast-forward to last night and the Glasgow Hilton when, in expanded terms, GB declared how he was now on board to enhance Holyrood. In an echo of Ms A when she spoke of her not being an "unthinking Unionist", the PM, in declaring his support for the Union, insisted: "Do not confuse that resolve with unthinking opposition to change and development in how our union governs itself."
He then said that while devolution had worked there was "a problem".

Namely, that while the Scottish Parliament was wholly accountable for the money it spent, it had no accountability for the money raised. Mr Brown then spoke about "developing" devolution.

The SNP reacted by claiming he had "caved in" to Nationalist pressure. There is some truth in this as there is no doubt in the contention that the PM has also bent to pressure from some of his own Labour colleagues in Scotland.

There are, of course, no specifics as yet on precisely what extra powers should be devolved. No doubt these will come post-Calman. But the reality is that, having for so long swum against the tide of general public opinion in Scotland, Mr Brown appears to have joined it. The direction of political travel seems clear: more powers for Holyrood.

If once Calman reports next year, the PM decides to do a reverse ferret, he will be engulfed. So it's now down to how to package the policy on devolution phase two. The chances are Labour will put their recommendations in the next General Election manifesto in the hope of taking the wind out of the SNP sails. Yet there will be still those Labour clansmen at Westminster who will feel decidely queasy at feeding the devolution beast. They will no doubt be warning their masters that it will not be satisfied by a few federal titbits and will ultimately want the whole pie.