Yesterday morning, I passed a group of boys of maybe eight years old playing football in a park in Berlin. When I was their age, that spot was in the death strip on the East German side of the Berlin Wall.

The Wall was built to prevent free movement—outward rather than inward—but today it manifests chiefly as different green men on the pedestrian crossings on each side.

Later in the day, I took the train to the airport. I didn’t have €3.30 in coins, and the ticket machine didn’t appear to accept notes, so I paid for my fare from a Euro account using my Belgian bank card. From the airport, I travelled back to London on an Irish passport.

Or, to put it another way, I paid for a ticket to an airport in an EU city with a bank card from an EU Euro account, then used an EU passport to fly within the EU. This is a completely normal thing, and yet now, after the Brexit vote, I can’t help but notice it.

To me, the reduction of borders, the free movement of people and goods, and the fact that you can use services, documentation and qualifications from one EU country in any other is a wonderful thing, and the UK now looks so dismally insular by comparison.

I miss the days when we were tearing down walls.