Do stronger borders ever work?: Leaders have thrown up walls and barriers throughout history – but their effects are unpredictable

Stronger borders don’t deter desperate souls fleeing war zones, the climate crisis or economic hardship. Not when they can be circumvented. As a travel journalist, I cross borders for a living. In the Spanish exclave of Ceuta, I saw how African migrants risked death to swim around the razor-wire fences and watchtowers guarding the EU’s land border with Morocco. Mexican cartels have carved long and sophisticated tunnels beneath Trump’s wall.

It could even be argued that stronger borders encourage migrants to stay on longer than they might do otherwise. Through much of the 20th century, Mexicans crossed the porous border into southern US states for seasonal work. Once the harvest was in, they’d go home. Now, having endured a dangerous and expensive passage into the US, they’re more likely to want to stay permanently.

It was when I travelled the 300-mile length of the Irish border that I really understood the absurdity of hard borders. There, I visited communities and even farmhouses that Ireland’s partition had cleaved in two a century ago. The concrete barricades that once blocked roads are now gone, but the trauma still reverberates. Not simply as a result of the loss of life during the Troubles, but in the border regions’ ongoing economic disadvantage compared with the rest of Ireland. The threat of this hard border returning after Brexit prompted many of the people I met there, regardless of their personal politics, to believe that Ireland’s future lies in reunification rather than continued division.