If he’s wise, he turns away then, and busies himself with his nets or his sails or with calculating how much longer his fresh water will hold out – for nothing good ever happens to a man who gets too close to a mermaid. But if he’s too foolish to realise that beautiful isn’t the same as friendly or gentle or even safe to go near, he’ll steer a little nearer, and call out to get their attention.

Then the mermaids will turn their faces towards him, and he’ll see that behind their crimson lips their teeth grow in jaggedy backward-slanting rows, and their nails are long and sharp, and their eyes are black with hunger. Then, even a moderately foolish seafarer will turn into the wind or (if the wind is flat) reach for his oars and row as hard and fast as he can without looking back. Once the mermaids have you in their sights, they don’t give up easily.

But if he’s very foolish indeed, he’ll notice that the faces and bodies of the mermaids have the perfect beauty of hunting animals in their prime, and his heart and his hands will begin to ache with longing. Just beneath the surface, the tails of the mermaids will twitch and flicker. And as they circle his boat, slowly first and then faster, creating a whirlpool, he’ll let his hand dip into the water to try and touch them as they pass.

The boats of these most foolish seafarers are never seen again, and even Davey Jones – who is just a man himself, and has learned the hard way not to interfere – can’t say precisely what happens to them. Most people say that the mermaids eat them, and then turn their vertebrae into cups and the tops of their skulls into bowls, and carve their shoulder blades into combs for their hair.

But for every nine people who swear one thing is true, there’ll always be a tenth who swears the opposite. In this case, the tenth person was an old blind man with a bald head and a waxed moustache and one leg and a hook for a hand, and a taste for the unspeakable black ale served in the sailor’s tavern at the very end of the world. When he got good and drunk he’d sing sea-shanties in spine-tingling harmonies, and when he began to sober up again he’d chew tobacco and tell stories about the things he’d seen in his seagoing days. And this man always said that sometimes, in the autumn and under a low hunter’s moon, a baby would come to shore in a basket made from driftwood, naked and new and screaming with hunger; and sometimes there’d be a gold armband or a raggedy hunk of whale blubber tucked in alongside, like a present, or perhaps like payment.

These babies, he said (between gobs of tobacco-spit) were the daughters of men and mermaids (always daughters, never sons), and they would be taken in and raised by the lonely fishermen’s wives who prowled the shore and waited for their men to come home to them.