It would be understandable if Yes campaigners took a jaundiced view along these lines: a large Ukip vote in the south indicates that England, in particular, is moving much more to the right.
This is not in line with the broader social democratic ethos north of the Border.
It reinforces the case for independence, as Scots are unlikely to get a government they actually voted for.
This view will be difficult to sustain if Ukip win one seat in Scotland and there is a possibility that they might do so under the proportional voting system used in the European polls.
It would provide Mr Farage and his colleagues with an enormous fillip. It is realistic in the sense that many disillusioned Conservative voters might turn to them, and not simply because of its stance on immigration. They may even feel that Ukip presents a stronger case for the maintenance of the Union than any of the other parties campaigning for a No vote.
By winning a Scottish seat, Ukip activists will be able to say that their remit goes much further than the affluent commuter belt suburbs.
It could put the pro-independence campaign on the back foot. The prospect of it happening should make sure that the European elections in Scotland have far more significance than many pundits realise.