So, is it a great white or not? I’m off to Pembrokeshire on Friday, a mere day or two’s hard finning from St Ives, so I need to know. The Times says that judging by the shape of the dorsal it’s a basking shark, or possibly a dolphin. Or one sighting was one and one was the other. The Sun, however, and its resident shark expert Dave “Sharkman” Baxter, who with a name like that ought to know, continues to insist it’s “the razor-toothed predator featured in the film Jaws”, a female man-eater. “And its mate will be close by.” Double trouble.

Forget Star Wars, I don’t worry too much about men in hoods coming after me with a length of fluorescent strip lighting. No, for sheer psychological impact, Jaws was the most influential film of my childhood. There hasn’t been a time over the past 30 years when I have been swimming anywhere other than a swimming pool (and sometimes there too) and not thought about being dismembered by a great white. I believe anyone of my generation and younger, or older, anyone who’s seen read or seen Jaws basically, will feel the same way. The Sun certainly thinks so: it’s put the shark on its front page three days running.

Fear, on occasions paralysed terror, has struck me in the North Sea, the Irish Sea, the Channel and yes, in the Atlantic off the coast of Cornwall (everywhere, really), when I’ve imagined a triangle knifing through the swell, or sensed a shape beneath it, and heard the music in my head. If I lived in Tewkesbury, I’d have thought twice before paddling down the street in a rubber dinghy. They like rubber dinghies, great whites, much as they like surfboards. They think they’re seals. Or maybe they’re just nasty.

Friends and family tell me not to be silly, great whites attack off Florida, the Cape, Australia, and then extremely rarely. But it’s like the stats that say crossing the street in London is infinitely more dangerous than flying to New York. Yes, it almost certainly isn’t going to happen . . . but if it does happen, the game’s up. With most forms of accident or violent encounter, you reckon, wisely or otherwise, you’ve got a chance. With a great white, evolved over 400 million years into the perfect underwater killing machine, even optimists recognise they’re dinner.

Besides, I have studied the subject. Peter Benchley wrote Jaws after researching a series of scoffings along the New Jersey shore. The water there isn’t so different from the water here. In principle there is no reason why a great white wouldn’t make a meal of you off Margate as off Miami. Indeed it is something of a marine mystery why they haven’t turned up here before. And now, whether they have or haven’t, I won’t be taking any chances at the beach. Swimming, waterskiing and rockpools deeper than 18 inches are no-go areas; my attention will instead be focused this summer on cricket, sandcastles and, through a pair of binoculars and from the safety of dry land, whatever is out there in the deep.

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