Ever since the North Sea oil beds were developed 10 years ago, Britain has played the role of a nemesis for the Organization of Petroleum Exporting Countries. As the largest noncommunist exporter outside the cartel, it has refused to cooperate in attempts to control prices and production, largely because of Prime Minister Margaret Thatcher's fervent free-market principles.

Despite a persistent global oil surplus, OPEC leader Saudi Arabia has doubled its production in recent months, saying it will no longer restrain output while others like Britain reap the benefit of high prices. With the world already awash in oil, the Saudi production boost has contributed to a sharp decline in prices, causing the value of Britain's North Sea crude to fall by more than 30 percent.

Saudi Oil Minister Ahmed Zaki Yamani clearly believes that he has taught Britain a lesson, as today's ultimatum for them to cooperate in limiting output indicated.

Yet Britain's policy has not budged from its staunch refusal to join OPEC in regulating the market. Even as the sterling exchange rate fell in response to the oil situation, and traders here waited anxiously today for the treasury to do something, the government remained unmoved.

Nonetheless, the sheer magnitude of the economic stakes involved in the current oil crisis appears likely to encourage an eventual truce between Britain and its OPEC rivals, according to oil experts. Britain is estimated to lose more than $700 million for every dollar drop in the price of a barrel of oil.

Nearly all analysts here -- in and out of government -- say they believe that an extremely rapid drop in oil prices much below where they are now, or a sustained price below $20, would be difficult for Britain to handle. Despite the extreme fluctuations over the past week, few expect either of those possibilities to occur.

The question, however, is who will blink first to prevent it -- the Saudis or the British. Some here say they believe Britain cannot hold out much longer. While they do not expect a publicly announced policy change, they predict that the government will take "covert" measures to lower production -- adjusting regulations governing peripheral aspects of production and indirectly forcing the North Sea companies to cut back.

"They will not admit it," said Paul Frankel, of London-based Petroleum Economics Ltd., "but there are many ways to do it." Frankel, while acknowledging that the situation remains volatile, says he is betting that the two sides will reach a private accommodation.

"When things get really bad," he said, "it concentrates the mind."

Already, some analysts say, there are signs. Production has fallen back from a November high of 2.7 million barrels a day to 2.6 million.

Two weeks ago, during a tour of the Persian Gulf region, British Foreign Secretary Geoffrey Howe suggested that Saudi and British energy officials meet to discuss the situation, but so far no such meeting has taken place.

"I think they'll cooperate," one oil executive said of the British. "I think these numbers scare the hell out of them." Below a $20-a-barrel price, he said, the relatively high cost of North Sea exploration and production begins to become prohibitive.

Despite an announcement by North Sea coproducer Norway that it was prepared to cooperate with OPEC, the energy department here said today that there was "no intention of interfering in the British sector North Sea oil production."

Lower oil prices may mean lost revenue for Britain, a treasury statement said, but they have their bright side. "The overall effects on both output and inflation . . . are expected to be broadly neutral," it said, "if anything, slightly beneficial."

Part of Britain's reluctance to cooperate with OPEC is attitudinal. This country, its officials frequently remind, is not an "oil" country. It is a manufacturing and trading nation, they note, with a nonoil economic base to support it. Since the mid-1970s, North Sea oil revenue has been most welcome, but everyone knows it will not last forever.

Saudi Arabia, one oil executive pointed out this week, "is nothing without money." Britain long survived without oil, and its officials take some pride -- misplaced in the view of some -- in saying that it will survive just as well long after the oil is gone.

Today's treasury statement pointed out that oil accounts for only 6 percent of Britain's national income, 8 percent of its total exports, and 8.5 percent of tax revenues.

Moreover, Britain is a democracy that finds a great deal of its own identity in its hands-off economic policies. The private oil companies that pump the oil are dependent on the world market to determine their production rates, not the perceived needs of the British government. If they decide that production should be lowered, they will lower it.

To top off Britain's case against the cartel, officials here point out that, even when OPEC's government-controlled companies agree on pricing and production arrangements, they often are the first to cheat each other. What, these officials ask, is to prevent the more flagrant OPEC abusers from cheating Britain -- picking up the production it curtails?

Britain's problem is complicated by the fact that Thatcher's government, in the throes of extreme political difficulty, has pledged popularity-boosting tax cuts of up to $5 billion this year. That figure was calculated on the optimistic basis of $16 billion in projected oil revenue from production averaging around 2.6 million barrels a day.

There are other financial factors at work, all of them interconnected. Thatcher's government has set low inflation as its top economic priority. Although secondary, low interest rates, a stable exchange rate and tax cuts are also important goals.

Progress in one area often interferes with another, however, and never more so than when "the City," as London's financial hub is called, gets nervous.

Although the mere prospect of lost oil revenue may not mean much in arithmetical terms, the sharply dropping prices of the past week have made the City nervous. When the City gets nervous, it and other international traders sell pounds, and the exchange rate drops.

A falling exchange rate also works to increase inflation. While partly offset by lower domestic energy costs, the equation eventually can reach a point of diminishing returns. To halt this, the government's most workable alternative is to increase interest rates. Already up by one percentage point in the past two weeks to 12.5, the base rate now is expected to climb to 14 percent. At least in the short term, that, too, becomes inflationary.

This is a worst case scenario. Many other economists here, however -- including those in the government -- argue that it also is an unrealistic prospect. The problems lower oil prices can cause are sustainable, they say, and the benefits are several.

A low oil price will lower domestic energy costs and increase the competitiveness of British goods while giving industry more money to expand and hire new workers. More workers means less government spending on unemployment benefits -- currently the largest government expenditure in this period of high joblessness. The more people employed, the more domestic expenditure on British products.

As Chancellor of the Exchequer Nigel Lawson put it in his December statement, "What we stand to lose on the swings, we stand to gain on the roundabouts."

As for the pound exchange rate, most economists agree that it has been too high at around $1.44, and feel its true value is around $1.30 -- where it now appears to be heading.

And even the tax cuts, they say, are not viewed as vital by the government. They will be even more welcome, this argument goes, in 1987, when the next general election is closer.

Even in economics, however, the issue sometimes returns to attitude and what the British feel is a simple sense of fairness. OPEC production is now up to 18 million barrels a day, about 40 percent of the world market. Britain's production is a mere 2.6 million barrels.

"Why should the United Kingdom take the brunt?" asked one oil market analyst. "OPEC always looks at Britain -- why don't they look at the U.S. or the U.S.S.R.? If you want to get it from non-OPEC countries, it should be spread around."