It is with immense interest that I have followed the correspondence re sharks in Diver's letters section. For months, I've bitten my tongue - not as convincingly as a bloody shark would have done, perhaps, but bitten it all the same. But now I feel I must speak out.
     I'm a reasonable, fair-minded, enlightened sort of fellow (as we divers go). But after long, sober reflection, it seems to me that the pro-shark lobby, as represented by your hello-clouds-hello-trees-weave-your-own-yoghurt brigade, should be strung up by the thumbs and machine-gunned.
     I say this with authority, because I have personally experienced the danger posed by sharks, as few of Diver's readership have done. You see, in 1976, when most of you were still in nappies, I saw Jaws.
     Many correspondents have dwelt on dwindling numbers of sharks, as if this were somehow to be deplored. But I learned from Steven Spielberg's admirable documentary, as did many of my generation, that you need only ONE of the bastards to wreak complete havoc.
     In the course of a holiday season, a single great white can bisect a score of attractive young women, ruin a perfectly sound hardboat and swallow distinguished marine biologists whole.
     In today's world, this sort of behaviour is simply unacceptable.
     In the May issue, Martin Leach protested that Jack's Fish & Chip Shop (Harpenden) was offering a free shark steak with every chicken dinner sold. This is blatantly unfair to chickens.
     Sharks are violently anti-social. Chickens, on the other hand, are generally peaceable and positively motivated creatures. When did you last hear of a diver being ripped limb from limb by a chicken?
     In my view, Jack should have been actively encouraged to extend the offer to two shark steaks with every carton of mushy peas.
     Sadly, it transpired that, far from cashing in on a promising market trend, Jack has ceased altogether to serve shark meat - not because he was converted by the bleeding-heart shark apologists, but simply because he couldn't obtain enough product.
     Why couldn't he? The Leaches of this world would claim, I'm sure, that over-fishing is threatening their beloved, sinister, blank-eyed alien killing machines with extinction.
     Bollocks. Sharks have been around for 400 million years (as argued by Lisa Chappell in the May issue). You don't imagine that a handful of Russian fish factories are going to put paid to the most successful creature on the planet after the red ant?
     When the puny little trawlers get within 100 miles of Shark City, the sharks know they're coming. That's because of the special audio-electronic smell sensors in their eyes.
     Sharks don't need passports. They don't have to put their houses up for sale. They don't have vanloads of furniture. Two-thirds of the Earth's surface is covered by water. When their electro-biochemical sense organs tell them that Harpenden Jack and his shark-steak hunters are only five days' sail away, what are they going to do?
     Exactly. They're going to move. My guess is that most of the sharks are now hanging out five miles down in the Marianas Trench, getting fat and happy on those freakish mutants with the traffic-light eyes and the teeth like Janet Street-Porter's.
     Make no mistake, Lisa - in a few million years' time, it's sharks who'll be buying fossilised human teeth, not the other way round.
     So I hope that's put the record straight. The guide books tell you that if a shark attacks you, thump it hard on the nose. My advice is, don't wait until it attacks - thump it anyway.