The city disappeared almost without warning. One moment we were leaving behind Heidelberg’s old streets, the Neckar River, the ruined red-sandstone castle high on the hillside, and the graceful arches of the Old Bridge. The next, our bus seemed to have entered a different Germany altogether.

Students marched. Cockroaches protested. And somewhere in between, an Indian tourist was desperately searching for a free toilet.

Paris did not simply welcome us. It put us through a little entrance exam, complete with cultural jet lag, linguistic curveballs, and a sudden realisation that the traffic rules here appear to have been designed by someone who once lost a bet with chaos.

In one astonishing day, we ‘invaded’ three countries. France, Belgium and the Netherlands fell before our comfortable tourist bus, and by night we had reached Frankfurt in Germany.

“Just five more minutes!” Those are the famous five minutes that never obey the household timer. In a Paris home, a 14-year-old boy is glued to his mobile phone. His mother shouts, “The food is getting cold!” His father, half angry and half pleading, says, “Put the phone down.” The boy turns around and says, “Dad, this is the last video."

It may sound far-fetched. Yet the question is no longer confined to political circles. In a London coffee house, a casual conversation about Britain’s future soon turned into a serious discussion about its unity.