I HOPE you’ve seen the powerful new poster campaign which celebrates the positive role immigrants play in the UK.

Each one features an individual. The Polish firefighter who has saved lives; the human rights barrister from Sri Lanka; the mental health nurse from Trinidad and Tobago; the Kenyan who has taught more than 2,400 students to speak English.

These are uplifting stories reminding us of the massive value new Scots and Britons bring and the fantastic contribution they make. It’s a timely reminder of how lucky we are to have them – and a reminder which has never been more necessary.

As the General Election campaign unfolds, the dark side is creeping in as casual racism seems to be starting to gain some traction. It’s deeply worrying, unpleasant – and in my case, personal.

Last week, a member of the SNP, Muhammad Shoaib, defected back to Labour, claiming that the SNP only want what he termed “coconut Pakistanis” rather than “pure” ones.

This remark was directly aimed at me. I’m an SNP General Election candidate born of a Pakistani father and a Welsh mother. “Coconut”, you see. Brown outside, white inside and of mixed race parentage.

Shoaib was aggrieved at – fortuitously, as it turns out – not being chosen as the SNP’s Westminster candidate for the Glasgow Central seat. He is now presumably nursing his wrath to keep it warm. But even considering the febrile atmosphere and bump and grind of the current election campaign, his remarks were profoundly shocking and utterly disgraceful. And of course they were personally hurtful to me and my family. We’re all of us a mix of different identities, and that’s a richness, not something to be scorned.

This sort of racist comment isn’t just unpleasant – it’s also probably illegal. A councillor in Bristol who six years ago called a colleague by the same term of abuse was reprimanded, suspended and finally charged. Despite apologising, she was convicted.

You would have expected Labour to be appalled at the use of this kind of language and to have expelled Shoaib without a moment’s delay. In fact, the silence from them has been deafening.

If they simply hope it’s going to go away, then they’re wrong. The remarks have also been attacked by two of the largest race equality bodies.

Dr Rami Ousta, Chief Executive of BEMIS (Black and Minority Infrastructure Scotland), has pointed out these sort of comments damage diversity, equality and active citizenship. He also questions what sort of message this language sends to young people. He said: “It is an insult to ethical, civil, social justice and equality principles at various levels.” Similar sentiments have been expressed by CEMVO (the Council of Ethnic Minority Voluntary Organisations), whose chief executive, Colin Lee, has commented that remarks like this “not only reflect badly on the character of a person, but also go towards fuelling racism within wider society”.

On top of this, the International Development Minister Humza Yousaf – who himself suffered racist abuse last month when Scotland’s one Ukip MEP compared him to the terrorist Abu Hamza – has now written to Jim Murphy calling for action to be taken.

I’d be surprised if Murphy responds. He hasn’t yet. Rather than expel Shoaib, he’s likely to bury his head in the sand and hope it all goes away. This is because Labour themselves seem now happy to play the immigration card in a highly unedifying and disturbing way.

Remember the infamous “Controls on Immigration – I’m Voting Labour” mugs they produced for sale a couple of weeks ago? Even one of their own MPs, Diane Abbott, condemned that as “shameful” and an “embarrassment”. Yet instead of removing them, they’ve made them into huge stage banners. It’s scandalous that a party which once claimed to champion equality and diversity has sunk to this level. But the reason is plain to see: in a close fought election with the Tories, Labour is scared Ukip will eat into their vote.

Jim Murphy’s stultifying silence is a direct consequence of Nigel Farage’s megaphone racism. Ukip have succeeded in pushing the bar on immigration firmly to the right, and Labour are taking the cowardly approach of shifting with it rather than engaging in vigorous and principled resistance.

If there’s anything which is supremely irrelevant to this election, it’s someone’s colour.

There are plenty of positive themes to fight this campaign on. The exciting future Scotland could have; gender equality; fairness; human rights and much, much more. These are the values which should inspire us. Values which racism cannot, should not and must not ever overcome.