If you're a grouse-hunting British aristocrat at heart, you'll be right at home in the men's departments this fall. America loves a lord, as Mark Twain discerned a century ago, and our chronic cultural envy has only been exacerbated in the past two years by an unrelenting deluge of Britannica: "Brideshead Revisited," "Chariots of Fire," "Masterpiece Theater" and the great national grovel over The Royal Wedding and Birth.

So somewhere up there in the mercenary whimsy-mills of Seventh Avenue, they've decided we're ready for a good long wallow in Anglophilia. Don't expect an entirely new look: Mainstream menswear stabilized several years ago with the return of traditional clothes. But the fashion industry abhors a vacuum, and this season they've filled it with sporting Tories. New along the sceptered aisles:

Sportcoats. When designers plug "country" styles this fall, they don't mean Merle Haggard. They're talking about those quarter-inch-thick bulletproof tweeds and big mossy sweaters we've come to associate with video Brits. The predominant patterns will be "hunting plaids," herringbones (some with stripes), houndstooth and "gun check." But the real news is in color. Background browns and grays will be lighter and suffused with epicene accent hues of green, lavender and rose. Woodward & Lothrop is heavy into heather, and Jack Gubanc, merchandise manager for Britches, is excited about his "muddy colors and earth tones," as well as mauve, taupe and teal (sounds like a law firm). The whole idea, of course, is to achieve that relaxed yet elegant Harold Abrahams/Sebastian Flyte look.

Even the most conservative vendors are thinking British. Andrew Heyman, men's clothing buyer at Lewis & Thos. Saltz, says that although "Washington is strictly a blue- gray town, the color spectrum for this fall anyway is opening up," and "some of the qoods are getting beefier."

Accent sweaters. They're the sine qua non of the Oxford gentry look, in a myriad of shaces and heavily textured: Fair Isles patterns, argyles, Jacquard weaves and various inlaid-looking motifs, often stressing the accent colors in coats. Many are cable-knit, some have that terminally nubby surface normally associated with rag rugs. "Crafty looking," says Katie Koe, fashion merchandising coordinator at Woodward & Lothrop, "Like your grandmother knit them." Others feature saddle shoulders or a sort of mini-shawl collar called "crossover neck," permitting an unimpeded view of the tie, which should be worn rampant.

Top this gear with a tweed coat, and the resulting avoirdupois -- suitable for ambulating the moors in a dank fog -- may raise some qualms. If you're already toting a fair amount of flab, isn't this rig 9olnq to make you look like a yarny mammoth? No problem, tubbo. Thanks to the mass fitness fetish, bulk is back; even our male models have been getting bigger every season. And what about the heat? Can this vast acreage of woolens be worn comfortably south of Saskatchewan? Stay cool. There's a safety net for the truly tweedy. Although manufacturers showed some mighty dense fabrics last year, Washington retailers all say they have bought the lighter weights. And don't fret, either, at the mix-and-don't-match look combining, say, a herringbone jacket with a striped shirt, a heather knit tie and four-color sweater. It may affront the conservative retina, but "pattern on pattern" is the word this year, says Katie Koe, and "layering is back."

Suits. Among the Briticisms, expect a little more texture in the fabric and a slightly higher percentage of earth tones and plaids. Also likely: a modest retreat from the three-piece hegemony of the past. Three years ago, 80 percent of Saltz suits were vested -- as Brooks' and Dash's are now. But this year, Saltz has dropped the vested interest to 50 percent. So has Woodward & Lothrop. One reason is price: The vest adds between $25 and $50 to the cost of a suit, no inconsiderable sum in a recession. And Koe believes that, even with cooler office temperatures, for most gents "the vest just hangs in the closet." Even William Tomlinson, manager of the L Street Brooks Brothers, thinks that in general, "the look is going to be a bit trimmer," "two-button suits are going to be more popular" and stretch fabrics are expected to expand.

Double-breasted coats. "Since 'Brideshead,'" Gubanc says, "there's been a resurgence in DB," as it's called in rag-biz argot. Brooks started them last year in three colors and will continue the trend this year, although most retailers target the look at a younger customer. "Not a lot of people can wear it," says Gubanc. "It's a lot of coat."

Pleated pants. This year, they will account for fully 50 percent of Britches' britches. Brooks is introducing Jem this season for the first time in years, and Woodward & Lothrop has plenty, too -- many with putatively British side tabs and watch pockets. Cuffs will hang in there at a conservative 18 inches.

Shirts. Look for even more white collars and cuffs on solid-colored bodies, as well as tattersalls and the wider-spaced stripes that are thought to be more English. Collar styles will stay pretty much the same, but thanks to post-Edwardian chic, you'll be seeing more collar pins and bars. And in a burst of bravado atavism, Woodward & Lothrop this year has resurrected the collar pieces under the tie knot -- was a torturous carotid tourniquet worn in the early 1960s by such noted Old World types as Frankie Avalon and Dick Clark. But now, since it elevates the tie, "it's neat, it's English, it's very Prince Charles," says Koe.

There will be a spate of Anglified oddments, including leather detailing, elbow patches and those little dangling flaps on the left lapel known as "throat latches," as well as more suspenders, bow ties and thick-textured woolly cravats. Brooks reports a new interest in Chesterfield collars, and they're expecting a brisk trade in "novelty trousers." (The term subsumes not only lined stadium pants, but more exotic specimens like the trousers embroidered with, uh, pheasants.)

More formal wear. The new Anglomania arrives simultaneously with a dapper snap in menswear generally. Not just the sherry-swilling country-squire look, but the whole five-fork-and-fingerbowl evening-clothes gestalt as well. "People are dressing up more," says Tomlinson, "and we're sellin9 more formal wear than ever." Wing collars are flying at Britches, Woodward & Lothrop is moving bib-front formal shirts as leisure wear, and Dash's reports increased tuxedo sales ever since the Reagan inaugural.

But what do you do if you're just an ordinary memo jockey at the Department of Pork Futures and you don't want to hit the Metro tunnel trussed up like some kind of fox-hunting dandy? Well, relax.

"We don't find very many people who want to make a personal fashion statement," says Saltz's Heyman. "They tend to dress the way the people they work for dress." And if your boss is Ronald Reagan, that could mean a new wardrobe. Brown suits, formerly the exclusive province of Wichita seed dealers and Tulsa Rotarians, were "an unacceptable dress code here," says Heyman. But "thanks to the man across the street," his customers have now started asking for them. He's also stocking a broader range of plaids, even some windowpanes.

And if you just want to buy what you did last year, you've come to the right town. Even on Seventh Avenue, menswear fashions change only by Lethargic increments, and Fed City is much slower. In fact, your average glacier is just roaring along by comparison. For years, the best-selling suit from Brooks to Woodward & Lothrop to Dash's has been the navy blue pin stripe ("In the trade, you call it money in the bank," says John Dash, head of Dash's Designers) followed by gray pin stripe and tan. Britches, which runs a seminar for retiring Pentagon brass who want to know how to dress for emergence into civilian life, absolutely insists that the first suit purchase be vested navy pin stripe. "It's the power suit," says Gubanc. The most popular sportcoat is still the blue blazer, with camel hair a close second (Dash moved some 4,000 camel jackets last year alone; "the best-selling item in this chain"). White shirts dominate sales, followed by blue and yellow, and the most dependable item in neckwear is invariably the burgundy foulard. Plus ca change, plus c'est la m'eme clothes.

"A lot of what you see in New York is just too fast for Washington," which is "always two to three years behind a major fad," says Saltz's Heyman. And even when they get here they often don't sell. In fact, ever since the bell-bottom spasm and infamous Nehru interlude of the late 1960s, retailers say, Washington has consistently rejected every major pop look, generally shunning side vents or skinny ties, and disdaining with equal indifference the French/Italian wing-shoulder invasion; the giant lapel and shirt-collar craze, with those behemoth neckties that made a knot-lump the size of a softball under your chin; and the Italian "unconstructed" style of "American Gi9olo" fame -- which looked like somebody had stumbled into the Ramada Inn curtains and then just gone ahead and worn 'em to dinner.

So Washington merchants rejoiced in the mid-1970s when inflation/recession began moving cost-conscious consumers back into the safety of traditional duds. The silhouette hasn't budged much since 1976, and the standard Washington Look is still a natural-shoulder single-breasted suit with lapels around 31/2 inches, ties 3 to 31/4 inches, shirt collars at 3 inches or slightly larger. Even John Dash, whose discount lines include the more highly shaped European cuts of Nino Cerruti, Pierre Cardin, Givenchy and Adolfo, sees a general trend toward a softer shoulder and more conservative look.

The resurgence of the traditional look in menswear intriguingly parallels the gradual wane of the women's movement, and there seems an undeniable element of macho backlash in recent developments. After all, the obsession with British nostalgia reflects not only our purported new interest in elegant, tailored appearance, but our mesmerized fascination with an era of male primogeniture in which the dominant sex strutted in impregnable tweeds and burly flannels, their Oxonion psyches yet untrammeled by social change.

A domestic parallel can be found in the sportwear emphasis on military stylings, the "Raiders of the Lost Ark" look (the whip seems significant here) and the astonishing ubiquity of the Bomber Jacket. The trend will continue this fall, although Britches is stressing a "flight jacket" in suede. "We've found that for many men, leather has a rough, less refined connotation." Koe of Woodward & Lothrop says that "bomber jackets are over," and that this year's leather boys will be wearing a belted blouson item, below hip length and cinched at the waist, with "functional detailing" and "plenty of zippers" (thank you, Erica Jong). But for die-hard bombardiers, Woodward & Lothrop is carrying a neo-bomber line in so-called "distressed lether," the cowhide counterpart of prefaded jeans. To achieve the proper patina of abuse, Koe says, the jacket manufacturer whacks away at it until it looks like something that crawled out of Clint Eastwood's basement. (This is a marketing ploy with enormous potential for, say, produce departments. "No it is not bruised, Madam. That is a 'distressed' tomato.") Still successful is the shearling coat with its embraceable-yew look. And fall sport knits -- with their bold color blocking, horizontal chest stripes and saddle shoulders -- seem designed to appeal to brawny self-images. "If you have a large chest and broad shoulders, you're gonna look enormous," says Koe.

Another potentially revolutionary trend: Males may have begun shopping by themselves. For years, retailers have watched in glee as harassed males prowled the racks, supervised by advisory wives or sweethearts. Koe believes that pink shirts would not have succeeded in Washington were it not that "women are pushing or influencing their husbands or boyfriends" to buy them. But Koe believes there is now a move away from distaff oversight: "More men are shopping for themselves because they're staying bachelors longer." So Woodward & Lothrop and Gentleman's Quarterly are teaming up next week with a new idea in sartorial self-help: a fashion show and body-care clinic specifically for men. In addition to the clothes demo ("to see how to put the looks together"), the boys will get advice on grooming and fitness, skin supplies like "scruffing lotion" and moisturizers, shaving tips and hair care. "It's a total life-style promotion," says Koe, and "it's about time."

Sebastian would have loved it.