If the Westminster car crash turns out to be a terrorist attack, this is what we should bear in mind

We have allowed the temperature of politics to get out of hand

There is a great deal that we do not precisely know about what appears to be the latest low-level terror attack at Westminster. However, like many you may have a terrible sinking feeling that, first, it could have been much worse and, second, it might not be unrelated to the heightened political tensions of the moment – across parties, across religious and political beliefs – across the country, in fact.

The “debate” about antisemitism, about the burqa and niqab, the hateful tone of so much that goes on in social media, the talk of traitors and treason, enemies of the people. If you want to see what racial or religious hatred looks like, you need not infiltrate some terror cell; just take a look at the comments left below the line on popular news websites, or surf around Twitter.

Sooner or later there was going to be a reckoning, a tangible act in response to the goading and climate of fear we seem to have generated in our peaceful land.

The truth is that this is the kind of low-level terror that is disturbingly easy to perpetrate. We would have to institute a police state in order to eliminate it, and even then you could not be certain of doing so. As we witnessed in the more deadly Westminster Bridge attack last year, in Borough Market, with the murder of Lee Rigby, you need only a car or van and some knives to inflict huge harm on innocent people. The same goes of the lorry attacks in Nice and Berlin. At the Manchester Arena and in the murder of Jo Cox, and in the Paris massacres, there were more sophisticated techniques deployed, which required sourcing materials and some expertise, but not that much when so much can be gleaned from the internet. Car bombings have been attempted in mainland Britain, but, as in so many benighted areas of the world, we can see how relatively simple they are to construct, and the huge impact that they have.

Only days ago we commemorated the dead in the Omagh bombing three decades ago, in which Irish Republican terrorists murdered 29 people and injured 220 others. It was a reminder that car bombings were once not unusual on the streets of the UK, and not so long ago. The IRA’s mainland Britain bombing campaign, of assassinations, letter bombs and explosions in crowded pubs, also remind us that the UK has been subject to domestic terror campaigns before.

We could, for the sake of those who live, work, visit and travel there, cordon off Parliament Square and make it a pedestrian-only zone. We could do the same with other high-profile potential targets in the capital. Yet we know that all that would do would be to relocate the acts of terror, not stop them.

Do we have get used to what they used to call in Northern Ireland during the Troubles an “acceptable level of violence”? We may not have much choice in these increasingly over-heated times, where political doubt turns to anxiety turns to fear turns to violence and revenge. The fear is always, as in Ulster, that tit-for-tat “revenge” attacks by vigilantes will follow, self-appointed “defence leagues”, threatening a spiral of violence. That’s what happened in Ireland.

We may be horrified by the idea of another possible attack, and, to a degree, relived that the violence was not far worse – it’s shocking, yes, but how many of us can claim to have been completely surprised? Is this the new normal?