When is a Unionist not a Unionist?

When he is Jim Murphy. New Jim's latest rebranding exercise insisting, despite all evidence to the contrary that he is not a Unionist, is his most audacious yet.

Following his neo-nationalist "New Clause Four" and his tweaking the noses of London Labour MPs over the mansion tax, this is a further attempt to plunge Scottish politics into a maelstrom of ideological confusion out of which, he hopes, will emerge a Labour Party that Scottish working class voters can once again identify with and vote for.

To try to change Labour's Scottish image so radically in such a short time invites ridicule. Jim Murphy was quite obviously a very prominent and outspoken Unionist before and during the referendum campaign. He even opposed further devolution of tax powers to Holyrood before the Smith commission was convened. Sinners can repenteth, for sure. But this is a conversion too slick.

However, on the Unionist point, he has history on his side, after a fashion. What he meant in his remarks to the Scottish Parliamentary Journalists Association was that, as a product of the Irish Catholic Labour tradition, he is not a capital "U" Unionist borne of Orange Protestantism. By that he means the Rangers-style Unionism that attracted many working class Scottish votes for the Scottish Conservative and Unionist Party in the last century.

Mind you, the old Scottish Unionist Party (it didn't become Conservative until 1965) wasn't unionist in the sense we would understand it today. For a start, the Union in its title referred to the Union with Ireland, not Scotland. The original SUP, created in 1912, was a coalition led by Unionist Liberals who rejected Gladstone's policy of Home Rule for Ireland and who merged with the much smaller Scottish Conservative Party.

This had nothing to do with opposition to Scottish nationalism, for the very good reason that there was then no Scottish nationalist party to oppose. The SNP didn't come into existence until 1934 and then it was electorally irrelevant for the next 30-odd years. The 1707 Union was unquestioned.

The Scottish Unionist Party was electorally successful because it straddled class divisions in the cause of the greater United Kingdom of Great Britain and Ireland. It also exploited sectarianism. Protestant trades unionists felt threatened by the influx of working class Catholic Irish people who migrated to west-central Scotland in the first half of the 20th Century.

My grandfather, a foreman in Weirs, didn't like Irish Catholics joining the work force because they undermined pay levels: shades of Ukip. The Church of Scotland produced an infamous report in 1923 called the The Menace of the Irish Race to our Scottish National Identity.

Ok, this is a bit too much history. The point is that this unionist revisionism can be too clever by half. Of course, Mr Murphy is not a flag-waving, Celtic-hating, Unionist. But he is clearly a unionist in the modern sense of the word and, despite what he says, it was the same unionism espoused by the many Conservatives attending his street campaign.

They were all part of the umbrella of Better Together. Mr Murphy made no obvious attempt to distance himself from George Osborne's "declaration on the pound" or other aspects of a negative and thoroughly Unionist campaign dominated by a conservative financial elite.

Mr Murphy's rhetorical wheeze is very much in the post-modern style of his new "chief of staff" John McTernan, a profoundly Unionist former adviser to Tony Blair. Mr McTernan knows his history and likes nothing better than to bamboozle political opponents by reinterpreting it for them. He will argue that Mr Murphy is only doing what all those Yes supporters were doing when they said they were "not nationalists but...". If the Nats can disown nationalism, why shouldn't Jim disown Unionism?

He has a point. But the Yes campaign mostly regarded themselves as nationalists, albeit of the civic variety. And the SNP has been in the rebranding game for at least 25 years. That was when it introduced the policy of independence in Europe, which drew a line under the old-style separatist nationalism more associated with the political right. The SNP is arguably a post-nationalist party, as its White Paper confirmed.

Mr Murphy and Mr McTernan are in a race against time trying to rebrand Scottish Labour as a rival neo-nationalist party of the social democratic left. It is a project fraught with risk. Like those climbers trying to free-climb El Capitan, it is fascinating to watch, though you feel that at any moment they could fall to their doom.

Their chutzpah is breathtaking but will anyone believe it? Mssrs Murphy and McTernan were enthusiastic supporters not just of the Union but of the market reforms in the NHS, university tuition fees and trades union reforms. Presumably Mr McTernan no longer favours tuition fees, prescription charges or private provision of public services.

But I'm not knocking this. If Labour is undergoing a sincere process of ideological repositioning that brings it more into line with mainstream political opinion in Scotland then that surely is a good thing. Far better than the schizophrenic Scottish Labour of old that tied itself in knots trying to reconcile its Scottish instincts with the political reality of being a "branch office", as Johann Lamont put it, of a party trying to appeal to voters in the south of England.

Change is good for politics. If nothing else, Labour's breakneck rebranding keeps the SNP on their toes. There have been signs of complacency within the Scottish Government as SNP membership has grown to stratospheric heights. Since her coronation, Nicola Sturgeon has yet to get fully into gear while her predecessor Alex Salmond has been hogging the spotlight as if he'd never abdicated. The SNP now appears to have two leaders, one of whom fancies himself as the next Deputy Prime Minister of the UK.

Setting up a 50-50 gender balanced cabinet is all very well, but many of SNP ministerial team are untested in the fire of frontline election politics. As we saw yesterday with the vote on an energy price cap, they have a real challenge on their hands, not least a highly professional, round-the-clock Labour opposition that is going to track them all the way to May 7.

The Yes Alliance days are gone for good. The SNP are on their own. Too much of their response to the new Labour leadership has been knee-jerk such as the sort of tribal animosity that you see on social media. Of course, what New Jim is trying to do is opportunistic, hypocritical even. But that's politics. The SNP would be better advised to welcome the change in Labour's rhetoric and then claim credit for it.

What better tribute to the success of the SNP, they should say, than having the new Labour leader say he is no longer a Unionist? They should embrace New Jim with open arms and remind voters that, if they want the real thing rather than the New Coke, they should stick with the SNP in May.