Do you ever lie awake at night, dreaming about annexing part of a neighbouring country? If so, you are not alone.

A recent opinion poll for the Pew Research Center reveals that startling numbers of Europeans are not satisfied with their nation’s borders. Asked whether there are “parts of neighbouring countries that really belong to us”, 67 per cent of Hungarians replied in the affirmative, as did 60 per cent of Greeks, 58 per cent of both Bulgarians and Turks, 53 per cent of Russians and 48 per cent of Poles. Such sentiments even lurk in western Europe — 37 per cent of Spaniards, 36 per cent of Italians and 30 per cent of Germans also agree with the statement.

In normal times, these kinds of ideas would not matter much. Hungarians, for example, can bemoan the 1920 Treaty of Trianon, which, as they see it, resulted in the loss of two-thirds of Hungarian land, without believing regaining that territory is a practical idea. The danger is that these are not normal times. The idea of annexation — long taboo in international politics — is creeping back into the global political discussion. The single most important development came with Russia’s seizure of Crimea from Ukraine in 2014. Only a motley crew of countries, including North Korea, Venezuela and Zimbabwe, have recognised Russian sovereignty over Crimea. But five years on, Moscow is tightening its grip on the territory. Most of the world now tacitly accepts that there is little prospect of Crimea being returned to Ukraine. In that sense, the annexation has worked.