Finland, Estonia, Latvia, Lithuania and Poland have announced they will leave the Ottawa Convention of 1997, which prohibits anti-personnel landmines. Later in June, all five states are expected to give the United Nations formal notice of their withdrawal, allowing them to manufacture, stockpile and deploy such munitions from the end of the year. Together, they guard 2,150 miles of Nato’s frontier with Russia and its client state of Belarus.

Military planners are already working out which expanses of European forest and lake land would be planted with these deadly devices, laden with high explosives and shrapnel, if Vladimir Putin were to mass his forces against the alliance.