RUPERT MURDOCH'S love-in with Alex Salmond when he visited Scotland last week to open News International's new presses set tongues wagging that the papers will shift their support behind the SNP.

Former Labour ministers could only look on uncomfortably as Murdoch and the first minister posed for the cameras, having apparently hit it off extremely well, although it was not the first time they met.

With Murdoch's reputation for backing winners part of his longstanding newspaper strategy, sources close to the News Corporation boss say that he is considering a shift of allegiance in Scotland.

The problem for the man they call the Dirty Digger is that the Scottish Sun could not have attacked the SNP more brutally than it did on election day back in May with its infamous splash with the SNP symbol in a noose - a move seen as excessive in many quarters.

If The Sun now reverts to its mid-90s Nationalist backing, it will be one of the most remarkable turnarounds in newspapers. Not only this, it would mean giving backing when no Scottish papers are pro-independence and few were even warm to the SNP at the May election.

Apart from the fact that Murdoch is said to have liked Salmond and seen him as a winner, his temptation for change is said to have been fuelled by a cooling on Gordon Brown in recent weeks.

Where until recently he was said to have been keen on the prime minister's prudent approach to politics, some now say that his faith in him has been shaken by Brown's U-turn on an autumn general election and subsequent financial reforms in the face of the credit crunch.

This has coincided with an impressive speech by Tory leader David Cameron, which recently had Irwin Stelzer, a close adviser to Murdoch, saying that the newspaper baron was thinking about going blue again.

If he did decide to ditch his 10-year dalliance with Labour, famously cultivated by Tony Blair, it is said that he would have little truck with supporting the party in Scotland.

This, of course, would leave the door open to a return to supporting the SNP. If it did happen, it would cement News International's reputation for political promiscuity north of the Border, representing its fourth change of allegiance in a generation, from Tory to SNP to Labour and back to SNP again.

David Dinsmore, editor of the Scottish Sun, refused to comment on whether this would happen, but privately he is not thought to be convinced that it will. With the general election now unlikely to happen before 2009, he is thought to believe it unnecessary to discuss it in any case.

The News International corporate affairs department did not return calls on the subject in time for going to press, but the image of Murdoch and Salmond grinning side-by-side on so many newspaper front pages last week is unlikely to be forgotten quickly.

It certainly looks hopeful for the first time in many years that another piece in the SNP's jigsaw for imposing its will on Scotland could soon fall into place.