"It's very dark. It's almost black." May Woodward, an office worker in central London, is holding an Oreo cookie in her hands. It's the first time she has ever seen one "in the flesh as opposed to on an American TV show," and she's not sure she likes what she sees. "It's the color of wet mud!" she complains. "And the bit ... looks like toothpaste rather than cream."

She twists and turns the cookie in her fingers, staring at it from every angle with a screwed-up look on her face that seems to say, "Gross!" not "Mmm, cookie time." You could be forgiven for thinking she's handling some dangerous alien element, Cookie Kryptonite, say, rather than one of the best-known biscuits in the Western hemisphere.

She bites, chews, raises an eyebrow, chews some more.

"OK, I get it," she says, finally. "I can see the attraction. It's very sweet." Suddenly she seems to change her mind. "Actually it's too sweet ... it's becoming mushy," she says, alarmed as tentative chewing becomes frantic munching to wolf the cookie down.

My impromptu taste test in Leicester Square is now attracting the attention of puzzled passersby giving us weird looks.

Ms. Woodward's verdict is that the Oreo is "too ... damp."

I tell her that, according to the ads, it should be "dunked" before eaten.

"In tea?" she asks. (Dipping biscuits – we Brits call all cookies "biscuits' – in a steaming hot cup of tea is an almost sacred ritual here.)

"No, in milk," I reply.

"Milk?! A biscuit dipped in milk? Who does that?"

"Apparently Americans do," I explain.

"Well, let them," she say dismissively. "I won't be doing it anytime soon." And with that, she disappears into a throng of pedestrians, nonplussed by what has been labeled here as "America's Favorite Cookie."

• • •

The Oreo has landed in Britain. And it is giving rise to a furious Battle of the Biscuits.

The classic sandwich cookie may be as familiar and nostalgia-inducing as, well, Mom's apple pie for Americans, but the majority of us here have never seen or tasted one. Until now.

Now, Kraft, the makers of what some Brits refer to as "the black-and-white biscuit" is launching it across the United Kingdom in an advertising campaign that makes it hard for anyone who lives and breathes to avoid the Oreo message. Big blue-and-white posters on the sides of our iconic red buses implore us to "Twist Lick Dunk." A new TV commercial shows a young boy teaching his scruffy dog how to eat an Oreo: "First you twist it. Then you lick it. Mmm. Then you dunk it," he says, sploshing his Oreo into a glass of milk. This will be the first time that many Brits have seen a biscuit dipped in milk.

Supermarkets nationwide are promoting Oreos right at the checkout stands where the wait gives shoppers time to contemplate the curiosity.

Kraft hopes the Oreo will capture Britain as it has America (with 419 billion Oreos sold since they first appeared in 1912).

Since its 1996 launch in China, the Oreo has become the No. 1 biscuit in that vast country. But the Chinese Oreo is very different from the American one – it has less sugar and it is a crispy cream-filled wafer. The version being launched in Britain is the exact same as the American one. Only the packaging has changed. At 74 pence ($1.44) a go, we Brits will get our Oreos in a long, thin tube.

No biscuit in Britain is as dark as an Oreo – even the classic Bourbon, two thin chocolate biscuits with a chocolate filling, is light brown. So admits Jocelyn McNulty, director of UK biscuits at Kraft Foods.

Some Britons might think the Oreo is strange-looking at first. But she's confident that they will fall for the Oreo and what she calls the "child-like, delightful ritual" of licking the cream and dipping it in milk.

Others disagree. One tabloid newspaper has attacked those "Yanks" who are trying to "snatch the biscuit from our mouths and replace [it] with a tackier piece of inferior confectionary." Another described the Oreo as "an imperial juggernaut of a biscuit backed by one of the world's biggest food companies."

Blimey. Will we Brits soon be twisting, licking, and dunking like there's no tomorrow or erecting biscuit embargoes against the colonial cookie?

• • •

Britain is more than just a "biscuit market," warns Stuart Payne, author of "A Nice Cup of Tea and a Sit Down." "There is a long history and culture in the way we consume our biscuits, and Oreo will have an uphill struggle convincing us to change our ways," he says.

We Brits are biscuit-mad. The British Department of Trade and Industry estimates that $3.1 billion is spent on biscuits here annually, and one newspaper estimated that the average Briton eats 1.5 tons of biscuits and cakes in his lifetime. There's the aforementioned chocolatey Bourbon; the Custard Cream, a vanilla-flavored biscuit with a baroque design stamped on it; the Rich Tea, a plain biscuit perfect for dunking in hot tea or coffee; the Jammie Dodger, a round shortbread sandwich of sticky raspberry jam. (My mouth watered as I typed that sentence.)

"Some of these biscuits have a history of 150 years," says Mr. Payne. He describes British biscuits as "thoroughbreds" specially designed – in a Darwinian process of the survival of the dippiest – over generations to suit British tastes. For example, he notes, "Our love of tea-dipping has influenced the selection of flour and the temperature at which biscuits are baked. Our biscuits are built for dunking."

Yet the Oreo, because of its high-sugar content, is "woeful" when it comes to being dunked in tea, he says. "In my experience, it dissolves. It's not a survivor in tea terms like the British biscuit is."

Eating biscuits in a certain way is part of British culture, says Payne. It goes back to the days when lots of people worked in factories, and the only thing they could squeeze into their 10-minute breaks was "a cup of tea and two Rich Tea biscuits." Biscuits had to be sturdy and satisfy hunger.

Payne's not convinced that Oreo can take on such a deep-rooted culture in which only the toughest, tea-complementing biscuits survive, in a society where offering someone a plate of Rich Tea, Custard Creams, or Jammie Dodgers is a way of expressing friendship, love, and concern.

• • •

Yet in a taste test in Borehamwood, north London, I found plenty of Oreo fans.

"They are absolutely yummy," said Anita Rawal, a personal assistant. "Our whole family likes them. My mother-in-law had to send them from Nepal before they were available here."

It seems that younger kids not so attached to the old Rich Tea culture, are especially keen on the new black-and-white invader. "My kid loves them he could eat them all day," observes Shak Shakir, a sales consultant.

Still, Faizaan Sackett, a recruitment consultant, has found himself "raging" at Oreo ads on buses, seeing them as part of "the American invasion of snacks.

"Before we know it, the next generation of kids will not know the word biscuit at all," he grumbles. "Whether it's fast food, TV chat-shows, or cookies, we must resist all that is American for the sake of our own souls."

• • •

Back near Leicester Square in a small supermarket, a woman takes a tube of Oreos off the shelf, briefly reads the label, and plops it in her shopping basket. I wonder if she knows that she has just unwittingly fired a shot in the cookie war. Probably not. She may just like to try a different sort of snack every now and then.