Political leaders and their aides have been typically quiet over the Christmas period, with one exception.

Press officers from the Scottish National Party appear to be working round the clock to fire out news releases on the hour.

Even on Boxing Day the SNP issued press releases calling for an inquiry into the insolvency industry and criticising the Ministry of Defence for having a "battalion" of press officers.

The highly active SNP press office illustrates a point made by Matthew Parris about successful political parties. Parris says there is a "force" which attaches itself to, and encourages, political success.

The Times acknowledged the success of the SNP – and its significance in deciding the future shape of the United Kingdom – when it awarded the title of Briton of the Year to Alex Salmond. Jonathan Freedland wrote in today's Guardian that the SNP leader and Scottish first minister achieved the remarkable feat in May of securing a parliamentary majority in an electoral system designed to encourage coalitions. This contrasts with David Cameron's failure to secure a parliamentary majority in an electoral system designed to discourage coalitions.

The silver-tongued Salmond showed why he is one of most supreme political operators on these islands when he was asked today on Radio 4's The World at One what he thought about being named as Briton of the Year:

Fantastic. Drake, Nelson, Salmond. I can see that half-back line. I'm not quite certain if that's a verdict on me being so good by the Times newspaper or your Westminster politicians being so awful. It is one of the two.

With his typical light touch, the first minister encouraged Cameron to head to Scotland to take the lead in the pro-Union campaign:

I think David Cameron is a great asset to the independence cause. So the more he speaks the more support we will get for independence.

These remarks go to the heart of a growing UK political crisis that few people outside Scotland have noticed. Freedland wrote that, for all his success, Salmond is struggling to persuade his fellow Scots to break from the rest of the UK. Support for independence "remains stubbornly pegged at about 38% or lower", he writes.

But Freedland argues that Salmond, who is embarking on a slow and cautious approach to a referendum, could swing independence through "sheer force of personality". This is where the quiet political crisis becomes apparent: there is no credible opposition to Salmond.

Even the Tories, who have just one Scottish MP, acknowledge that they are at best a marginal force in Scotland where their brand is still contaminated by memories of Margaret Thatcher. The Liberal Democrats, who have been damaged in Scotland after signing up as junior UK coalition partners to the Tories, are struggling after losing a nominal twelve seats at Holyrood. They now have five MSPs.

That leaves just one pro-Union party in Scotland capable of confronting Salmond – the Labour party. Labour is blessed with remarkably talented Scottish politicians. There is just one problem. They all sit at Westminster. The four front rank Labour Scottish politicians are the former chancellor Alistair Darling, the shadow foreign secretary Douglas Alexander, the shadow defence secretary Jim Murphy and the shadow Scottish secretary, Margaret Curran.* Gordon Brown has written himself out of the script by refusing to attend the House of Commons more than a few times a year. John Reid is a big beast but he sits in the Lords.

There are some outstanding younger Scottish Labour politicians. Gregg McClymont and Anas Sarwar spring to mind. But they too have spurned careers at Holyrood, making it difficult for them to lead a campaign against Salmond, even though Sarwar is the party's deputy leader in Scotland.

One person is therefore charged with the responsibility of taking the pro-Union campaign to Salmond and, essentially, saving the United Kingdom. Step forward Johann Lamont, the new leader of the Labour party in Scotland.

Lamont acknowledged the scale of the task in an interview with Severin Carrell just before Christmas. Carrell wrote that Lamont performed well in her first formal encounter with him in Holyrood.

Lamont may unsettle Salmond in the Holyrood chamber. But with the best will in the world it is difficult to see how she can punch at the same level as the first minister who is one of the UK's three great political communicators over the last 20 years, along with Tony Blair and Cameron.

Labour's heavy hitters have turned their backs on Holyrood because they want to sit in a UK cabinet. In the case of Alexander and Murphy they want to represent a state on the world stage which is one of the five permanent members of the UN security council. If they are not careful they may find there are no Scottish MPs in the UK cabinet as Scotland slips out of the Union.

* To be fair, two of the four were elected to Westminster before the Scottish parliament was approved in the September 1997 referendum. Darling was first elected in 1987 while Murphy was elected in May 1997. Alexander was first elected at a byelection two months after the referendum. Curran was first elected to Westminster last year.