JUST whose useful idiot is Sean Clerkin?

Four years age he was seen by few deluded cheerleaders to be of benefit to the SNP when Labour leader Iain Gray lost authority by running away from the loud-mouthed, self-appointed campaigner.

The Nationalists had even shown the profound lack of judgment to let him stand as a council candidate for them before he parted company with the party.

Now his megaphone lack of diplomacy has actually helped a Labour leader, giving Jim Murphy his much wanted victim moment, not unlike the egg-throwing incident during his referendum campaign Irn-Bru crate tour.

But bellowing intolerance, shouting down others' freedom of speech, is always idiotic and if that actually damages the cause - whether to the SNP in this campaign or to the wider anti-austerity movement - this particular idiot really doesn't care because it's all about him and the monstrous ego that substitutes for lack of achievement.

Scotland's finest lyricist, Aidan Moffat, mocked himself in a song for the "ramblings of a lonely solipsist" but that would be a fair description Mr Clerkin, who likes to hog the limelight during election campaigns but either doesn't care what damage he does to the causes he is meant to be espousing, or is too blinded by his own self-importance to care.

I have always cherished humour on the campaign trail because, at the most basic level, it is what elevates tribal differences to political respect. The Nationalist threads on Twitter and on Facebook are buzzing with humour, while a beleaguered few are responding for Labour.

If Labour are reborn as an outsider, renegade party once more, having cast aside their role as Scotland's establishment, we may see humour to the fore once more.

But for now the Nationalists are miles ahead, with the SexySalmond Twitter feed running rings round Labour. Who could have imagined that a fake Alex Salmond Twitter account might have reached this level of engagement? It has spawned copies but AngrySalmond sets a benchmark for humour and engagement, in language that is second only to a fake MalcolmTucker account for that vital mix of humour and surrealism (and sweary words).

Humour goes beyond the web, and it helps if it's that little bit surreal - like the trick tricyclist present at the Eddie Izzard protest who shot to fame during the referendum for his Star Wars "bow to your imperial masters" protest. Noisy, no doubt, but it was nothing like the ugly moment when Mr Clerkin screamed in Mr Murphy's face from inches away.

But the London broadcasters have continued to wax lyrical about Nicola Sturgeon. Why? Because she has broken all their rules, from fighting her way through massive street events to outrageously risky photo stunts such as walking a gymnastic beam.

Experienced broadcasters such as Alex Thomson of Channel Four have come to Scotland and reported a welcome change from the pattern of leaders in closed bubbles. But he too reported on the Clerkin affair, rightly calling it an unsavoury attempt to shout rivals down. Yet Labour actually welcomed it. As leading Scottish Labour blogger Duncan Hothersall said in a Tweet: "Sean Clerkin is going to confront Eddie Izzard? Please let there be cameras."

That says it all. At that moment there could be no good outcome for whatever cause Mr Clerkin imagined he was espousing because his chosen tools, volume, lack of humour and simplistic slogans, were certain to rebound in favour of Mr Murphy at such an event as the Labour leader could, rightly, be indignant about "the ugly face of nationalism". Innocent shoppers passing by were horrified, particularly the one who spoke of her "traumatised" children. She was a Labour election agent, as it turned out, but this mattered not.

Humour, self-deprecation, and tolerance for the views of others are the way to win over potential supporters, or at least avoid alienating them.