Immigration has had a positive social and economic influence on Scotland.

Although this is an opinion piece, these are facts. Much of what is written about immigration is increasingly not about facts. A poisonous and divisive agenda, led by Ukip, is now setting UK policy. The Conservatives, and increasingly the Labour party, are playing along and doing little to challenge this.

The myth that immigrants come to Scotland to live off benefits, costing the state while contributing nothing, has now been repeated to the extent that many have accepted it to be true.

That it is not true is worryingly becoming irrelevant to the debate. This is despite countless academic studies providing various ­positive figures for the contributions made by immigrants. Indeed, only a month ago, research from the University College London showed that European immigrants contributed 64% more in taxes than they received in benefits. Previously, migrants from outside the EU have been shown to be contributors, and students alone bring £779 million to Scotland every year.

This seems to be increasingly irrelevant to the Home Office. Chasing policies built upon the lies of Ukip is clearly a problem across the rest of the UK, but it is ­devastating in the case of Scotland.

Unlike England and Wales, the ­Scottish population has not ­markedly increased since 1980 and the need for a young, dynamic work force has never been greater.

Economic realities aside - and much ink has been spilt on them already - there is much more at stake. A fundamental question about us. What sort of a country do we want to be? Internationalist, open and collaborative or narrow-minded, closed and divisive? Recently, the UK Government's policies have become ­increasingly damaging to the extent that we have now reached a position where Scots are having their loved ones torn from their arms and sent overseas. This piece was provoked by receiving such an account from a constituent.

Although I'm not easily shocked, the news that the UK Government won't let you marry unless you're earning more than £18,600 a year does chill me. It is horrifying that we now live as part of a country where around half of the population does not make enough money for them to be allowed to marry anyone they choose. This also discriminates against women in particular.

The level set by the Home Office appears to have been plucked from thin air and is nearly £5500 a year more than the minimum wage. This salary must be earned by the UK citizen, resulting in bizarre ­situations in which somebody with a highly paid job cannot come to Scotland because their partner has made the decision to look after their children.

The European Convention on Human Rights clearly outlines that every EU citizen has a right to a family life. The rules clearly discriminate against lower-income families.

At the very best, the UK Government's policy is on dubious ground here. I have written to Theresa May asking to see the legal guidance that the UK Government is using to defend the current ­immigration rules and I look forward to her response.

Unwarranted desire to reduce immigration should never result in families being torn apart, children being separated from parents and young couples fleeing abroad so they can live together. This is the reality of the current situation.

The UK Government must stop pandering to Ukip and learn that if it wishes to be taken seriously in the world it must not only obey the law but also behave in a decent and humanitarian way.

If every country had a policy as backward as this then much of the world's population would have their choice of partner and family dictated to them by their governments.

Let me be clear: the people of Scotland have not bought into Ukip's lies despite the very best efforts of some sections of the UK media.

Even with the wall-to-wall ­coverage Ukip have received, opinion polls have illustrated that support for immigration in Scotland is consistently higher than south of the Border.

This in turn is reflected in the far higher levels of support that Ukip receive outside of Scotland. In turn, more than half of Scots support devolving immigration to the Scottish Government, yet the Smith Commission has maintained it should remain a UK policy.

What Scotland needs is a rational, compassionate and humanitarian immigration policy.

So long as Ukip are setting the agenda, it is unlikely we will get one.