IF EVER there was a valuable piece of advice given to me by Great- grandfather Arnold all those years ago as I sat by his knees while he sucked on his Old Scrag, it was most surely this: "Never, Ever Trust a Boffin." And the truth of this richly Arnoldian aphorism was never made more plain to me than this week, as I perused with astonishment the assorted eggheads holding forth in the newspapers on the subject of Bovine Spongiform Encephalopathy (dread gibberish).

I have been an enthusiastic beef eater all my life. Morning, noon and night, house guests in Chateau Arnold find that assorted cuts of beef, beef and more beef are freely available: roast rib on the television in the drawing room, chump in the servants' quarters, a chilled consomme with parsley and cream in the toothmugs in all the bathrooms, perfect little pats of steak tartare on the pillows in the guest bedrooms and, for our American cousins, big rissoles next to the floral soaps in the shower rack.

Never has a day gone by without a tasty bit of beef slipping its merry way down the Arnold throat. I start the day with a goodly wedge of Beef Dripping poured daintily - but with all due generosity! - over my Scott's Porage Oats. When I am feeling really naughty(!) I then treat myself to another spoonful (or three) in my breakfast cup of Earl Grey, and jolly good it is too. And so to elevenses, where a simple Penguin chocolate biscuit can be greatly enhanced by the addition of a few slices of lightly roasted beef plus oodles of horseradish and a pinch of nutmeg.

Come luncheon, I tend to fall back on that Great British Standby: a decent joint of beef. This must, perforce, be served rare, or ''still kicking'' as my grandmother would call it. It has been said that a gentleman who manages to conclude his luncheon without a sizeable splash of blood on his necktie is no gentleman at all. Personally, I end my own luncheons looking rather as if Mr Jackson Pollock had just paid a lightning visit, and my friends are well used to the spectacle of my good self parading along the streets of London come the afternoon with little flecks of blood and gristle attached to my jacket, to be devoured a few minutes later as an essential part of a light afternoon tea.

For dinner, I tend to favour a little more beef. As a first course, I acquaint my stomach with a couple of dainty beef vol-au-vents on a bed of lightly curried beef, to be followed by a delicious beef goulash, Olde English Beef stew or beef curry, depending upon mood, with a goodly slab of Mr Wall's Ice Cream plus a couple of spoonfuls of Beef Jelly as a pud. For my savoury, I tend to favour something a little lighter: a minute steak, perhaps, or a decent piece of tongue, or a lightly-poached oxtail with a cheese sauce. And last of all, in deference to the Health Lobby, I try to manage a lettuce leaf with my mug of steaming hot Bovril.

Marvellous! But now the politically motivated scaremongers seem utterly determined to spread their home-grown variety of rumour, gossip and innuendo. Yet the fact remains that though this may afford them some amoosement, it is highly destructive to our national dish. They claim that Bovine Spongiform Encephalopathy (dread moothful) may well transfer to human beings. But this is, at best, a mooot point. Personally, I have found no sign whatsoever, either in myself or in my close friends, that the consumption of beef products results in any form of human Mootation.

To celebrate our continued allegiance to beef, a grooop of us gathered at the Beefsteak Club on Thursday last to hear Mr Douglas Hogg propose a generous toast to the bull and cow. I have to say, it was mooosic to my ears, and when he sat down he acknowledged our applause with a snort and wave of the hoof. The delightful performance of our second guest, Mr John Selwyn Gummer, was equally memooorable. Gummer brought along his dear daughter, Miranda, whom he was only too happy to force-feed on beefburger a full five years when this ridiculous ''Mad Cow'' scare first began. Miranda, I need hardly say, has never looked more healthy or happy, wagging her tail from left to right throughout the speeches.

The big guns of the BSE lobby are, as you see, somewhat short of amooonition. My body and brain will continue to be oiled by beef for many mooonths yet, regardless of the scaremooongers, who I don't believe for one moooment. Mad Cow disease, forsooth! The very mention of such an absurdity makes me want to lie on my back and wiggle my legs, front and back, in the air. In short, something mooost be done.