The fact that there has never been a recorded sighting of anything larger than a family-size cod has done nothing to allay this strange, irrational fear. Now another, even more sinister, threat has materialised, in the shape of a giant tidal wave that lashes the coastline whenever the giant Sena superferry leaves Harwich and sets course for the Hook of Holland.
The worst-affected town to date is Felixstowe. Only the other day, five- foot-high waves came roaring up the bench, knocking holidaymakers off their feet, pinning them up against the sea wall, washing away pushchairs, handbags, radios, car keys, bikini tops and goodness knows what else, leaving them shocked, soaked and feeling glad to be still alive.
For some, the incident brought back memories of the war - such as Mrs Pauline Byford, who was on the beech at Felixstowe with her grandchildren when the wave struck: "I was brought up in the Blitz and it reminded me of that," she said. "One minute I was sitting there watching the sea, and the next I was under water, absolutely drenched from head to toe." A sector coastguard compared it with Dunkirk.
Though this astonishing vessel is only slightly smaller than the Canary Wharf tower and makes several crossings a day in each direction, I have yet to see it for myself, or suffer from its backwash.
However, there are many here in Thorpeness and Aldeburgh who claim to have felt its effects. The Sena people say they are looking into the incident, but then that's what the mayor said in Jaws.
The awful thing is that, although we own a house here, and spend a fair amount of time in it during the year, until we arrived here at the end of July we were quite unaware of this latest threat to the well-being of the locality. Small wonder the locals and full-timers look askance at us part-time countryfolk.
For most of the year, we are completely preoccupied with typical townie problems - the traffic congestion, the paucity of parking spaces, the pros and cons of various mayoral candidates, the latest offerings at the Almeida. Yet, within moments of taking up residence in Thorpeness, all the big issues of the day become a distant memory and we are up in arms over local dramas that we never hitherto knew existed. Not least the great Bentwaters Debate.
It is five years since the Americans left, and the last of the sinister A10 fighter bombers came booming in over the marshes at the end of yet another training mission. For a long time, the place was deserted. The windows of the residential blocks looked blankly out over the runway, the miles of taxi tracks and the ugly clumps of HAS (Hardened Aircraft Shelters). There was talk of the flats being filled with the poor and needy; then, of some kind of industrial estate. The latest plan is that it should become an international air park (an airport, in other words) with, eventually 80,000 scheduled, charter, freight and private flights a year - that's to say, one every three minutes.
And guess where the flight path will be. Slap over our house. Admittedly, at that stage they'll still be a few thousand feet up, and maybe property values will not have plummeted quite as dramatically as many fear; but, by the time they get to the Snape Maltings, five miles from the runway, they'll be on their final approach and rattling the eardrums of birds, concert-goers and anyone else unlucky enough to be in the area at the time. When the Americans were here, they came to an agreement with the Aldeburgh Festival people that they wouldn't fly over during concerts or recordings. To date no such undertaking has been received, and consequently this area is at war with Bentwaters.
Most of the letters received by the Suffolk Coastal District Council are against, but a recent telephone poll resulted in a shock 60-40 vote in favour. Some are convinced it will never happen; others that any public enquiry will be a whitewash job and it will all go ahead willy-nilly, like Sizewell B. The debate rages on.
Then there's the long-running hoo-ha about the location of the dog exclusion zone on the beach outside our gate; and the future of the Playing Fields in Aldeburgh; and the lack of rain along the coastal strip. Never mind, though. Any day now, the holidays will be over, there'll be black plastic bags outside every gate, and we'll all be back to real life in London, and not have to think about low-flying 767s or giant waves again until - well - next summer.