Euan McColm: Attacking Britishness will only damage Nationalist cause MORE than a decade ago, something occurred to the brightest young things in the SNP: the success of the party, and the broader independence movement, was completely dependent on their ability to connect with voters who felt British. This realisation that, unless things changed, their political arguments would repeatedly hit a sizeable wall of red, white and blue was a long time coming. The SNP, after all, had always recognised the power of emotional Scottishness. But key party figures finally realised Britishness mattered and that seemed like substantial progress. And then they did very little about it. The SNP of the turn of the century was a party resigned to perpetual failure. Yes, it made strategic sense to start building a dual carriageway along which Scottishness and Britishness could travel in parallel, but what was the point? They were never going to win... Instead, the Nationalists - rattled by a slump in support and riven by internal party conflicts - reverted to the old ­language of division and mistrust. In 2003, then leader John Swinney made a furious conference speech in which he roared the Nats" mission to tell the "Brits to get off." To the great credit of the ­ordinarily thoughtful Swinney, he still cringes at the memory. This weekend, as Deputy First Minister Nicola Sturgeon - lead Cabinet Secretary on referendum matters - meets with ­fellow campaigners, the issue of identity will be back, a priority among the many "work-streams" leading towards the 2014 independence referendum. There is a recognition - not just in the SNP, but across the YesScotland campaign - that British identity remains the most difficult thing to argue around using mere logic. Scottish identity is no less complex, despite Alex Salmond's success in telling us a Pixar-movie-perfect version of who we are. But it's the Britishness thing that has Nationalists worried. The SNP machine is something to ­observe. Place in front of it a tangible, three-dimensional problem or issue and watch all the parts work. There is a good reason the party has started winning ­elections. But Britishness is a peculiar thing: it's difficult to detect - and often difficult to explain. Take a random 42-year-old man, with some sense of British identity. YesScotland may be able to persuade him to vote for the break up of the UK, but alongside providing answers on education, the NHS and all the things that we say matter most, they may also have to locate in his body, and then surgically remove, half a dozen Philip Larkin poems, a black-haired girl from Torquay, and the exotic, sharp red-brick of Manchester. And even after that, there could still be quite a bit of Les Dawson in there, and a chip shop in Whitby. I wonder how YesScotland changes the mind of a man who, as a seven-year-old in the Hebrides in 1958, sat by the wireless listening to news of the Munich air disaster involving the Manchester United team and felt a wave of empathy that created in his mind an unbreakable bond between Lewis and Lancashire. I don't see any greater chance of success with a young woman for whom The Beatles don't represent just a soundtrack to life, but - in memories of those songs being played by cherished uncles - create a stream on which she and her family can sail from the Tay directly into the Mersey. The existence of these subtleties may be recognised by Sturgeon, but that doesn't make her task any simpler. How does she persuade BetterTogether sympathisers to break from the rest of the UK when each individual's sense of Britishness is an impenetrable, epic poem of images and associations, both vivid and only half-remembered? It's too late. The language of the debate was allowed to take a fiercely anti-British tone for too long after clever Nationalists knew it was referendum suicide. Anyone who combines an interest in Scottish politics with an addiction to ­Twitter will remember the farcical volte face made by SNP MP Pete Wishart ­during the London Olympics. Wishart had expended a great deal of time and energy attacking the downright terribleness of the Games, sniping about cost and disproportionate benefits to the south. As soon as public reaction in Scotland to the Games proved Wishart had wasted his time on a pointless negativity trip, he became Team GB's number one supporter. In moments of particular shamelessness, Wishart lambasted unionist opponents for politicising the Games. There could be no better illustration of how easily this issue of British identity can be misjudged by Nationalists. Rather than clumsily addressing Britishness - felt to some degree by a majority of Scots - Sturgeon would be advised to perform a little sleight of hand. Her mantra should be Scottish empowerment rather than Scottish independence. She will hope, too, that activists and less thoughtful Nationalist politicians take greater care with the language they use. Crude attacks on the "British State," "imperialism," and the union flag are destructive to the independence cause. Even greater pressure to remain ­positive about Britishness will come in the next year as BetterTogether begins introducing high-profile figures from outside Scotland in an emotionally driven campaign around the message "please stay." The "no" campaign has the upper hand here - they know Britishness exists and their support for it is completely plausible. Nationalists, on the other hand, have a huge challenge. Maybe too great. Because when Scots are asked to give up part of the UK in 2014, many will feel that they are being asked to give up part of themselves.