ONE of my first tasks after I started work as a journalist at a small Yorkshire daily five years ago this week was to deal with a chap in reception.

This was no one-off visitor. As unpleasant as he was unhinged, he became at least a once-daily nuisance. Foul-mouthed, complete with his own distinctive odour and a whisky miniature perpetually poking from his shirt pocket, it didn't take long to discover he was openly racist. He also happened to be the town's most vocal supporter of Ukip.

This week, I came across a Facebook group called The Scottish Resistance which, it says, is "dedicated to restoring Scotland's Independence from the brainwashing power of the Westminster imperial masters".

One particular incident involving that old drunk sprang to mind. He had arrived at the office in a particularly animated state. We should run a story, he bellowed, on the basis of a letter he had received from the Ukip hierarchy. It had been diplomatically worded, thanking him for his enduring enthusiasm for the cause. But its message was clear: "Stop campaigning - you're doing us far more harm than good."

It got me thinking when, or if, the SNP leadership would send a similar message to the types attracted to that Facebook page. The Scottish Resistance has gained 1,300 members in five weeks, small fry compared to the 100,000 who have signed an online petition calling for a referendum revote due to "countless evidences of fraud".

The ludicrous views expressed there - for example that senior Yes strategists had been covertly working for Westminster all along - are not representative of the 1.6 million who backed independence, nor the SNP which has some of the brightest minds in the country.

But in the age of social media the lunatic fringes are more troublesome for political movements than ever before. The page was highlighted by Unionists on Twitter and the danger is clear - a vocal minority can damage a cause by association in the minds of the very people whose backing is essential if it is ever to succeed.

Think of the Tea Party movement in America. Fiscal fundamentalism and characters like Sarah Palin might play well in the heartlands, but less so with voters in swing-states such as Florida and Ohio which went Democrat in 2008 and 2012. Closer to home, do crusty peace campers do the anti-nuclear movement much good in the minds of the masses?

So far, the SNP have taken a softly-softly approach with pro-independence extremists. Its leaders accept the referendum result unequivocally, they say, but they've hardly been shouting it from the rooftops. Alex Salmond has even fanned the flames, hinting Holyrood could one day declare independence without a referendum while a claim Scotland could break away from the UK with a majority of SNP MPs north of the Border is gaining traction.

Nicola Surgeon will soon become SNP leader, First Minister and - starting next week - speak to tens of thousands on a tour of Scotland. It presents an opportunity to deliver a public version of that letter to the Ukip buffoon and loudly disassociate her party from the zealots.