When, at the end of January, Poland’s deputy interior minister, Maciej Wąsik, said his country had “to be prepared for a wave of up to a million people” in the event of a major Russian invasion of Ukraine, many thought he was exaggerating. Just five days after the military attack ordered by Putin, over 280,000 Ukrainians have entered Poland. At this rate, Warsaw could be facing Europe’s largest wave of refugees since the second world war.