This week we commemorate the anniversary of D-Day. Seventy-five years ago today, thousands of young soldiers made the ultimate sacrifice as the liberation of western Europe began. By the end of the battle of Normandy there would be more than 400,000 casualties.

In the shadow of the Second World War, the European Union’s predecessor, the European Coal and Steel Community (ECSC), was founded to foster economic cooperation and ensure that nations that had been engaged in centuries of bloody wars would never do so again. The idea worked – the EU has been the most successful peace project in human history, and it is because of it that generations of Europeans have been broadly able to take peace on the continent for granted.

Even Winston Churchill, often feted by right wing politicians yet referred to as the ‘Father of Europe’, warned after the war of the “dangers to us in standing aloof”. We should therefore not be surprised he approved our application to join the European Community.

Tory leadership frontrunner, and unashamed hard Brexiteer, Boris Johnson, credited Churchill for these ideas to bring European countries together, writing: “Together with Nato, the European Community, now Union, has helped to deliver a period of peace and prosperity for its people.”

Now, with the prospect of the UK leaving the EU, we could be turning our backs on the single most important reason Europe has been at peace since 1945.

In that same vein, 20 years after the Good Friday Agreement was signed, ending decades of violence on the island of Ireland, we can see the prospect of Brexit entirely unravelling the still young and fragile peace process in Northern Ireland. While the EU has been supporting peace initiatives in Northern Ireland for decades, the majority of Tory leadership candidates have made undoing the ‘Irish backstop’ or forcing through a no deal Brexit – both of which would see the resurrection of a hard border – central to their bids.

You don’t have to look far for examples of this callous approach to peace. Last year, Boris Johnson wrote to Theresa May with the astonishing claim that it was “wrong to see the task as maintaining no border” on the island of Ireland post-Brexit, despite promising during the referendum campaign that the border would be left “absolutely unchanged.” Andrea Leadsom too reportedly had no qualms about imposing direct rule on Northern Ireland if it came to it, with the caveat that it would be given a trendy new name.

And no-one for a second believes Nigel Farage would choose peace over the project which has catapulted him to fame.

With around 70% of my own constituents and two-thirds of the country now backing a public vote according to polling commissioned by Best for Britain, there’s more than enough justification for putting Brexit back to the people. As someone who served in Afghanistan and saw the consequences of war and violence, peace is just one of the many reasons why I back giving the public a final say on any Brexit deal with the option to stay in the EU.

That said it’s a bloody important reason. We must also not take for granted the peace which has been built through hard work and cooperation with our European partners over the last three-quarters of a century.

This D-Day, we should all spend some time reflecting on that. For the best way to honour the fallen is to prevent future generations from repeating history’s mistakes.

Clive Lewis is the Labour MP for Norwich South and a supporter of Best for Britain, a political campaign to stop Brexit