NORWICH, ENGLAND -- In Britain, war is brewing. The cause is independence, and the struggle is over the survival of something long considered an embodiment of the British character -- its ale. As in the thick stuff served at room temperature in a pint glass. The stuff through which no light passes. The stuff that may soon be extinct.

"Real" ale, as purists call it, is made almost exclusively by Britain's 135 independent regional brewers. For the last twenty-odd years, however, they've been under siege by the country's six corporate breweries. The corporates have threatened to monopolize Britain's pubs. They're replacing the traditional brews, strong enough to be sold as liqueurs in the United States, with biteless, mass-produced lager beers barely distinguishable from Budweiser or Coors.

Local brews are sweet or bitter, heavy or light, according to the taste of the region. The slick Londoner might drink one of the sharp, hoppy brews from Kent. The dark, mild ales of the Midlands' industrial areas, for example, are traditionally low in alcohol for the steelworker who wants to prolong or avoid a descent into oblivion at the end of the day. Someone from Manchester, in the north of England, would probably find both wimpy, preferring the creamy, robust beer of his hometown.

No wonder, then, that so many should be repulsed by beer designed to please everyone.

The real ale the independent breweries produce is technically referred to as "cask-conditioned" beer. It has no artificial carbonation, but just enough natural carbonation to give it a head. The pourer has to crank mightily to get it from the keg to the glass.

Because such beer is not pasteurized, purists consider it "alive" and carbonated beers like Budweiser or Coors "dead." Like any other living thing, real ale has a life span -- generally about two weeks. "Dead" beer, on the other hand, lasts indefinitely and is slightly cheaper because of it.

The economic implications are clear: Britain may be on the way to losing forever one of the closest things it has to a national cuisine. And a grass-roots organization, the Campaign for Real Ale (CAMRA), is trying to ensure that this doesn't happen.

"We're just trying to get more people involved," says Neil MacLeod, the representative for CAMRA in the eastern town of Norwich. "We want the average bloke to realize 'Hey! I don't have to drink lager,' " he says.

The latest skirmishing has been over the status of the pub, a venerable British institution where, in spite of toughening national drinking-age laws, the young are usually old enough to buy their first pint when they can see over the bar.

There are two kinds of pubs: "free houses" -- free to sell whatever brews they choose -- and pubs "tied" to the giant breweries and obligated by contract to sell only their brands. A year ago more than a third of the country's 83,000 pubs were tied to the so-called "Big Six" breweries -- Allied-Lyons, Bass, Grand Metropolitan, Scottish & Newcastle, Courage and Whitbread.

Then the government stepped in. In March 1989, responding to the lobbying of CAMRA, among other pressures, the Monopolies and Mergers Commission issued a report suggesting that the Big Six, along with the other breweries, be allowed to own only 2,000 pubs each. Lord Young, Britain's secretary of state for trade and industry at the time, said he was "minded to implement" these changes.

But three months later, Prime Minister Margaret Thatcher's government, which has a reputation for not backing down, backed down. With the help of a massive advertising campaign, public statements from the clergy and a few whispered reminders of the Big Six's political clout into the ears of Parliament, the corporates forced a compromise of Young's plan.

The final government proposal was heavily watered down by the addition of several provisions. One recommended that pubs owned by the Big Six be allowed to operate free of their ties to them and sell whatever "guest" brands they chose in addition to the brewery's own. CAMRA as well as the British press immediately pointed out, however, that few tied pub owners can afford to ignore the advice of their giant landlords when deciding which beers to serve at their establishments.

The original limit of 2,000 pubs remained, but in a weakened form. Breweries with many more than 2,000 pubs in their name are required to sell off only half the pubs over that number, still leaving some of the giants in control of many thousands of pubs.

The Big Six also found loopholes within the proposal. The limit on ownership extends to brewers alone. Nearly all of the Big Six entities are giant corporations diversified into many areas: hotel chains, fast-food operations and so on. If one of them finds retailing more lucrative than running breweries, it may sell off those breweries and concentrate solely on running pubs (as many as it wants) that sell ales brewed by other Big Six breweries. At present, for instance, Grand Metropolitan is looking to trade its breweries for Courage's pubs. Allied-Lyons also must decide whether to adhere to the rule of 2,000 pubs or sell off its breweries.

The loss of their brands of beer is inconsequential to the Big Six, according to MacLeod. "The Big Six don't exist for brewing; they exist for making money. They're not so much concerned with the preservation of their beer as the preservation of what lines their pockets," he says.

A group of concerned beer drinkers formed CAMRA in 1971, the year of the now-infamous "Red Revolution." The revolution was Watney's introduction of its Red Barrel line of beer, the first "dead" beer to be made available in British pubs. Since then, pasteurized beers have dominated sales at pubs all across Britain. As the threat has spread, so too have CAMRA branches. Nearly 25,000 Britons have been concerned enough to join.

The issue is most alarming to the generations that can remember the time before the Red Revolution. Up until then, real ale was virtually the only thing pubs sold. It had been that way for hundreds of years.

Jim Bartlett, an Oxford native and student of British culture, is a conscientious beer drinker as well. He notes that ale was a staple in the times when water was not purified. Brewing ale, he says, "was a way of keeping water safe to drink. It killed all the bugs. Centuries ago when a mother sent her children to fetch things for her, they'd get water from the well for washing and ale from the pub for drinking."

Bartlett, who is in his early forties, thinks that most Britons still want to have the choice to drink something worthwhile. "Some people here still travel a long way for a good pint," he says.

To CAMRA, the fight is also a matter of preserving a way of life. "We want to maintain the traditional pub with its traditional atmosphere," says MacLeod.

Many Big Six pubs are referred to as "theme pubs." Their atmosphere is akin to that of nightclubs in the United States with their ear-thumping music, dim lighting and disco ball-centered decor. The lager they serve, to the palate of the real ale drinker, is watery and expensive.

"The British pub is famous for just the opposite," says MacLeod. "A traditional pub usually has a landlord and landlady behind the bar, with two pumps of local ales. If there is any music, it's low in the background or it's a jig band maybe." The center of attraction is meant to be the ale, a gauge for the out-of-towner of his surroundings.

"If you compare Norfolk ale to Yorkshire's, for example, there will be a different flavor," says MacLeod. "Norfolk water is very hard, so there's not such a creamy head. Yorkshire water makes for a softer, creamier pint."

CAMRA reminds casual drinkers of the variety and quality they would be missing if they let the Big Six have their way. Its main venues for reaching the public are beer festivals it organizes at the regional level, where small breweries can set up booths and let Britons become beer connoisseurs for a day.

The independents brew everything from relatively mild brews to syrupy concoctions that can knock you to the floor. Pubs in Norwich, for example, may carry Woodforde's Headcracker, notorious for its sweetness and alcohol content of roughly 6 percent alcohol, nearly double that of Budweiser.

For their part, the Big Six breweries see themselves as the protectors of real ale. While aggressively marketing their own pasteurized beers that are cheaper and that can still induce intoxication, the corporate brewers can keep the independents alive by buying them.

Michael Reynolds, a spokesman for Courage, says the battle is entirely a matter of survival of the most financially fit. "We expect that consumer choice and demand will ensure the continued success of the very best of the products produced by brewers -- whether national or regional," he says, adding that Courage plans to "build cask ale sales even further in the future."

The Monopolies and Mergers Commission proposal went into effect May 1. Since then, CAMRA has been busy informing publicans (pub owners) of their rights. "We've been sending letters saying, 'Do you know you are allowed to have guest beers?' to publicans. We've been telling them that their patrons don't have to drink the bland beers of the Big Six," says MacLeod.

Officials from the government Office of Fair Trading also have been making it clear to publicans that attempts by the Big Six to force them not to sell guest beers are illegal.

CAMRA has charged that the Big Six have been playing dirty in recent weeks. The organization says the Big Six bring up the subject of rent increases while conversing with those tenants considering stocking guest beers.

Thus far, four of the Big Six breweries have been content to stick with their own lucrative brewing operations, which means that they will have to sell off a great many of their pubs. Whether they will find a way to thrive as brewers and pub owners simultaneously remains to be seen.

"We'll still have a lot of police work to do, making sure things go as they should," says MacLeod. "As long as the Big Six have their beers in pubs, we will keep on reminding people that life doesn't end at lager."