There was a great deal of watery imagery in the letter, many references to waves and floating – and some mention of light and air. There was no mention of the earth: no suggestion of returning to dust, no fruits of the loins, none of the traditional allusions to death and decay. There were no childhood anecdotes, no sentimental references to any of the signposts of growth other than his birth. By the end of the letter Maurice was in splendour, while his mother remained in the water. The letter represented a kind of voyage through her most intimate emotions, from the water to the sky, to a crescendo of grief and a kind of serenity.

But none of this provided much concrete information.

Were there any clues in the name itself? After all, the name made up half the certain facts about the boy: that he was called Maurice and was aged thirteen. Was there a region in France that produced most of the Maurices? It seemed unlikely.

In the catalogue of saints, Maurice was a Roman soldier, martyred around ad 287 in modern-day Switzerland, patron saint of infantrymen, dyers and weavers. He was particularly called upon by those suffering from cramps. His feast-day was 22 September. According to various name dictionaries, Maurice had no particular regional links.

It is an old-fashioned name. An uncommon name. A name from the turn of the century – even from the last century. A name linked to that archetypical Frenchman, Maurice Chevalier, who thanked Heaven for little girls.

Perhaps not a name for the child of a Parisian intellectual. More likely to be a name for a worker at a Renault factory. A name for a fisherman. Or, in this case, a name for a dead child.

After translating the letter I had sent it back to my friend. She had refolded it exactly as it had been, and with great difficulty reinserted it into the narrow neck of the bottle and placed it on a kitchen shelf, with her other beach flotsam, where she occasionally glanced at it while doing the washing-up. Although our friendship was close, we seldom met, since she rarely visited London, and the only time I had gone to her house in Kent had been for her wedding many years before. We talked on the phone often, but we only met once every two or three years, and always in London. But I was obsessed with the letter she had found, and wanted to know more. I wanted to know what the bottle looked like – in her somewhat inarticulate way she had said it was different and beautiful. How could a bottle be beautiful? Or different, for that matter? In retrospect I now realize that my willingness to undertake the three-hour drive from the wrong side of London to one of Kent’s less accessible corners should have warned me that I was becoming sucked into something. But, at the time, I made excuses about not having seen her for a while and suggested I come down for lunch. I asked whether I could see the bottle, and whether she could show me the beach where she had found it.