In February, my sister and I took the ferry from Dover to Dunkirk. On the way back, I noticed there was a deal: spend €150 (£130) in duty free and get a free day-trip ticket. If you love Toblerone and know anyone who smokes, you can spend that without even blinking – and so it came to pass that I was back on the ferry within a month.

This was when I started to perfect the art of the day trip, even though I didn’t yet realise this would be the beginning of a beautiful loop. You arrive and go to the coast, which looks like Saint-Tropez when the sun is out, because even though Dunkirk is not a famous holiday destination, it is still France. Then you go to Carrefour and spend ages saying: “How is this fizzy wine €4.68? I wonder if it’ll be nice. Only one way to find out – buy 24 bottles of it.” You get back on the boat to return to Britain, which is where things get weird, because the offer is still on. Well, I still love Toblerone and I still know someone who smokes.

So I was ready for another day trip, but I’d lost my receipt from the last one. Getting ready to chalk the whole thing up to experience and never see France again, I explained myself to the ferry company and they gave me another day trip. I can’t tell you the name of the company, unfortunately, because if we all start doing it they may get rattled and pull the offer.

On the third trip, it dawned on me that I could work on the crossing, which is two hours each way. Factoring in the way being at sea sharpens concentration, this is effectively a day’s work, a holiday and an exercise in hedonic thrift, all in a lot less than 24 hours.

So now I have urgent business back in France. I need to get more crémant – it tasted like champagne, FYI – in time for my divorce barrister’s wedding. There are people who want to come in convoy; their trip won’t be free, of course, but their next one will be. I don’t know anyone who doesn’t love Toblerone. I feel as if I’ve turned the port into a magic portal.