As voters gear up to decide this week whether Britain should stay in or leave the European Union, Vanessa Baird makes a case for fear – and political realism.

Both sides in the unedifying debate over whether Britain should remain in or leave the European Union accuse each other of stoking up irrational fear.

But sometimes it is right to be afraid. The question is: what are you more afraid of?

Up until Thursday last, the media was dominated by economics – there were endless claims and counter claims, statistics trotted out and spun to suit whichever purpose. If you believed one side you’d be richer out of the EU; the other you’d be very much poorer.

Then came the tragic killing of Labour MP, humanitarian, and ‘remain’ campaigner, Jo Cox. The man charged with her murder, Thomas Mair, is allegedly linked to the far-right Britain First group, and gave his name in court as ‘Death to Traitors, Freedom for Britain’.

To their credit the campaigners on both sides agreed to shut up for a few days.

Now the big question surely is: ‘What kind of society do we want to live in?’

What kind of door do we want to have open? The one that welcomes diversity and what that brings? Or the door that is open to fascism and all that follows?

‘Fascism’ – an emotive term that doubtless leaves me open to accusations that I too am partaking in ‘project fear’.

But Europe has been here before. It has seen populism stoked by xenophobia and fear of the other.

And there are signs aplenty of what, just a few years ago, was considered right-wing bigotry, casually moving into the mainstream.

Anti-terrorist efforts in Britain are overwhelmingly focussed on the threat of Wahhabist Islamic extremism. Now suddenly we hear – many of us for the first time – of extreme nationalist groups like Britain First (described as a fascist paramilitary group) and websites like Redwatch (that publishes photos and personal information about anti-fascists in politics, unions, advocacy groups, the media).

While all the major parties in Britain have vowed not to contest the West Yorkshire seat left by murdered MP Jo Cox, a former member of the fascist British National Party, Jack Buckby, has declared he will stand for another far-right group Liberty GB.

Satisfying though it would be to give the Conservative leadership two fingers and either vote ‘Brexit’ or abstain, a ‘leave’ vote in Thursday’s referendum may be less a ‘no’ to David Cameron’s conservatives than a ‘yes’ to Nigel Farage’s racist and anti-immigration UK Independence Party and their ilk. (Ragnar Weilandt has written a good and measured piece on why ‘Left wingers for Brexit need to wake up to what they are about to do’.)

Equally worrying is the domino effect throughout mainland Europe, as others on the xenophobic Right draw encouragement from the prospect of a ‘leave’ vote. Dutch politician Geert Wilders, vehemently anti-immigrant and Islamophobic, is looking forward to Brexit provoking a dismantling of the European Union.

I’m not suggesting, of course, that everyone who wishes to vote ‘leave’ subscribes to isolationist and intolerant views. And although the EU’s achievements are notable (progressive environmental protection, family-friendly labour rights, equality legislation and comparative post-war peace in Europe) there are also many reasons to be highly critical of how the EU functions and dysfunctions. (Oddly, Greeks have more reason than most to complain, and yet remain generally pro-EU.)

I could go on about how it’s easier to change an organization from within than without… But I think more crucial right now is the issue of political culture and the compelling likelihood that Brexit will fuel ideologies that will give women, minorities, workers, immigrants and anyone who is prepared to stand up for the environment, good reason to fear.

Is saying this tantamount to fear mongering? To engaging in ‘Project Fear’.

Well, I’m not afraid to be afraid on this issue. Not afraid to be afraid of the power of populist, ‘patriotic’ movements with an inchoate catch-all appeal to anyone with a complaint.

There was plenty to grumble about in Germany between the two World Wars.

Imagine how differently the 20th century might have turned out if the German electorate had been a bit more fearful of that new, populist and nationalist party that offered an ‘answer’ to their problems…