FORGET the weather, we have a new national obsession: immigration. That’s right, while not so long ago it was little more than the hobby horse of Nigel Farage and his swivel-eyed you-know-who brigade, immigration - and people’s widely divergent views on it - has come to dominate practically every public debate.

Take the SNP. The ruling party has long been making noises that Scotland - and an independent Scotland in particular - needs an influx of working-age immigrants to keep its economy afloat, and earlier this year it made the case for Scotland taking control of its own borders regardless of whether it remains part of the UK or not.

The bid has met with a mixed response from the public, with respected pollster Sir John Curtice finding in January that 63 per cent of Scots wanted to keep the same immigration rules as the UK, while a report issued last week by the National Conversation on Immigration suggested that practically the same proportion (64%) now back immigration devolution.

Part of the reason for the flip-flopping is likely to do with the focus on the benefits immigration brings to the economy as a whole, with little attention given to how it impacts on us individually. Yet you only need to look at the state pension, a benefit every one of us should expect to receive sooner or later, to see the difference greater immigration could make.

It is no secret that Scotland has a rapidly ageing population and in its Sustainable Growth Commission report the SNP noted that while the country’s pensioner population is expected to grow by 28% in the next 25 years the working-age population will grow by just 1%. This matters because, contrary to popular opinion, our tax and national insurance contributions are not being collected in individual state-pension pots to be paid out on retirement, but rather are being used to fund current pensioners’ monthly payments, just as future generations’ taxes will be used to pay ours. It also matters in the context of the independence debate because in the UK as a whole the pensioner population is expected to grow by 33% and the working-age population by 11%, meaning the need for increased immigration, while still there, is less pressing.

The implication of this is clear: without a marked increase in the working-age population, an independent Scotland would be unable to continue paying the state pension - a benefit we should all be entitled to in some shape or form – without taking drastic, and electorally unpopular, action such as increasing taxes or raising the retirement age.

We all know how popular the former idea is, and the UK Government’s plan to press ahead with the latter has met with significant opposition north of the Border due to life expectancy in some parts of Scotland being so low. Increasing immigration, and so the tax take, would have the potential to negate the need for doing either.

Of course this is all moot for now, with a Home Office-commissioned report issued last week by the independent Migration Advisory Committee concluding that “Scotland’s economic situation is [not] sufficiently different from that of the rest of the UK to justify a very different migration policy”.

There will be some in the yes campaign that say this only strengthens the argument for independence, but the problem is that those shouting loudest for a second referendum appear to be the least likely to embrace an increase in immigration on any scale, let alone the scale an independent Scotland would require in order to thrive.

It should come as no surprise that there exists a scepticism towards incomers when a hard-core of indy supporters so vocally hanker after a country that is ours alone. Indeed, ahead of the 2014 independence referendum St Andrews academic David McCollum led a study that found “evidence of some (growing) hostility towards migration on the part of the general public in Scotland and a possible link between nationalist leanings and opposition to ‘Others’”. This opposition appears to have crystallised into the backward-looking ‘this land is our land-ism’ of the kind of die-hard secessionist who believes that screening Mel Gibson’s Braveheart at a rally will strengthen the indy cause.

Regardless of political stance, as an electorate we are always asked to make binary decisions - him or her, red or blue, in or out, yes or no - when the implications of those decisions are anything but black and white. In the normal course of events backing the wrong horse doesn’t matter too much because another election will always come along to let you change your mind. With referendums, however, the decision is far more binding, meaning voters will have to sacrifice some of their beliefs in favour of other, more palatable ones.

While some in the electorate may have independence at the top of their wish list and will do anything to get the chance to vote for it, the truth is that if immigration is not up there with it then even the staunchest of independentistas would be better off sticking with the UK, in all its Brexity glory.