Sitting in a small dinghy in darkness as it took on water was frightening enough in a sea survival exercise let alone for real

As I paddled through crashing waves in the darkness, stomach churning, I watched our small dinghy starting to fill up with water with a sinking feeling – it wouldn’t be long before we went overboard, and I was worried that at least one person in my boat was paddling in the wrong direction. But, then again, it might have been me: I was wielding an oar twice my size and it was impossible to tell in the frenzy.

Before we knew it the odyssey was over and the lights were back on. I emerged soaked through – with aching muscles and shot nerves – relieved to be out of the water.

This was the RNLI’s sea survival pool, used to train volunteers in the rigours of life-or-death aquatic rescue. All I had done was traverse a 25-metre swimming pool four times, but it was enough to assure me that repeating that at least 325 more times across the Channel would be a deeply traumatic experience. What’s more, it is a journey that would probably be much longer as a migrant is, in many cases, guided by only a smartphone compass.