With thousands of chanting, placard-waving protesters outside, British Prime Minister Margaret Thatcher told her Conservative Party's annual conference here today she is determined to pursue her monetarist economic policies in defiance of public unhappiness and growing criticism from senior party figures.

Playing to still-loyal party activists packing the conference hall, Thatcher said she "cannot bow to the pressures" from critics seeking emergency measures to alleviate unemployment.

"I will not change just to court popularity," she said in what was regarded as a particularly important speech for the embattled prime minister.

Her firm public stand today sets the stage for expected confrontations over economic strategy with her increasingly bold opponents inside the party. Her economic ministers are seeking to bring down inflation with more than $10 billion in budget cuts for next year. But her opponents on the Conservative benches in Parliament and inside what is now an almost evenly divided Cabinet want instead to increase spending by almost the same amount for job creation, public works and aid to industry to spur recovery from Britain's worst recession in a half century.

Some dissident government ministers said privately this week they still expect Thatcher to agree under pressure to some policy modifications, whether or not she changes her rhetoric. But today she disappointed party elders who sought a softening of the aggressive Thatcher style, which they fear is alienating all but hard-core Conservative voters.

The increasingly bitter political and social divisions in the country were symbolized by today's large and noisy protest march outside the conference hall, just as its labor union and radical left-wing political organizers had intended. While well-dressed Conservative delegates filed into the hall, up to 10,000 demonstrators filled the streets of the seaside center of this northern working class resort town, chanting, "Kick the Tories out" and "Maggie, Maggie, Maggie, Out, Out, Out."

They carried scores of official union local banners from northern England and Scotland, where unemployment has increased the most halfway through the Thatcher government's five-year term. Thousands of police, many on horseback, sealed off the conference hall and the streets around it to all but delegates and the media, although a few demonstrators managed to sneak inside and yell insults at Thatcher before being hustled back out.

"It makes it more exciting, doesn't it," Thatcher ad-libbed after the outburst. "We are dealing with one of the most complex and sensitive problems of our time," she said about Britain's record unemployment rate, which is now more than 11 percent of the work force. "Neither rhetoric nor compassion is enough, and demonstrating won't help either."

She said she welcomed the unprecedented display of dissent by a significant number of senior Conservatives during this week's conference and understood "the fact that many people who have worked loyally and well for firms up and down the country feel bruised and resentful when, after long and devoted service, they suddenly find themselves without a job."

But, in answer to the contentions of critics that her monetarist policies have worsened the recession and increased unemployment, she blamed the problem mostly on world conditions and, in Britain, "enormous past wage increases unmatched by higher output, union restrictive practices, overmanning, strikes, indifferent management, and the mistaken belief that, come what may, the government would always step in to bail out companies in difficulty."

Referring to the suggestions of her critics, she said, "There have been many voices in the past few weeks calling on us to spend our way back towards a higher level of employment, and to cut interest rates at the same time." She said this would only lead to higher inflation and "a collapse of trust in the pound sterling both at home and abroad and the destruction of the savings of every family."

"Of course," she said, "there are those who promise success without tears. How I wish they were right . . . I can tell you unhesitatingly that if I thought that Britain would solve her problems more easily, if I found that world conditions opened up a less rugged road, I should not hesitate to take it.

"There are those who say our nation no longer has the stomach for the fight," she declared. "I think I know our people and I know they do."

Following the open rebellion early this week by senior Conservatives outside the government, several members of Thatcher's Cabinet known to be unhappy with her economic philosophy, combative rhetoric and autocratic leadership style have also made their differences known in thinly veiled speeches. They echoed the rebels' warnings about damage being done to the country and the Conservative Party and joined the calls for a more pragmatic and conciliatory approach.

Cabinet member James Prior, recently shifted by Thatcher from employment to Northern Ireland secretary, referred to inner city areas where high unemployment rates have been cited as a cause for recent rioting.

"When you look at Liverpool, Birmingham, Manchester or Belfast," he told a rump meeting of Conservatives seeking to reverse the party's rightward shift under Thatcher, "you see that you can't do it all through the private sector as some would have us believe. We do have to have considerable public expenditure if you want to turn that sort of thing around."

House of Commons leader Francis Pym, a senior Cabinet member widely regarded by Conservative members of Parliament as Thatcher's most likely successor if she lost the party leadership, warned that voters would abandon the Conservatives "if we are not able to convince people we are still the party of one nation."

Thatcher's supporters continued to respond in kind.

"What we are being offered by Thatcher's critics is little more than cold defeat dressed up as high principles," Nigel Lawson, a former treasury minister who is now energy secretary, told a meeting of Thatcher loyalists. "It is very close to bribery dressed up as statesmanship."

Norman Tebbit, recently promoted by Thatcher to employment secretary, said some of the 3 million unemployed "are less keen to find work than others." Recalling that his own father was thrown out of work during the 1930s depression, Tebbit added to robust applause from the party activists, "He didn't riot. He got on his bike and looked for work."