As Britain enters a harsh economic winter with a still worsening recession, rising unemployment, plummeting production and failing businesses, dissent is building against the austere monetarist policies of Prime Minister Margaret Thatcher's Conservative government.

Businessmen are loudly complaining about being squeezed too tightly, unions are fighting new pay curbs, defense chiefs are trying to fend off military spending cuts, a growing number of Conservatives are questioning their own government's direction, and the opposition Labor Party is stepping up protests in the name of the poor and jobless.

In the most dramatic demonstration of dissent so far, Labor members of Parliament protested against a government decision to steeply raise public housing rents last night in the House of Commons by physically disrupting the traditional ceremony ending an 18-month session of Parliament.

Angered when the government tried to slip the rent decision through in a nondebatable written announcement in the Parliament's waning hours, Labor legislators lined up five deep across the entrance of the wood-paneled chamber to block the crown's messenger "Black Rod," from summoning them to the nearby House of Lords to formally end the session.

While the House of Lords was left waiting for nearly an hour, the speaker of the House of Commons twice suspended business amidst tumultuous shouting and angry shoving before the government agreed to put off the rent increase decision until the new year-long session of Parliament that begins Thursday.

The Conservative leader of the house, Norman St. John-Stevas, accused newly elected opposition leader Michael Foot of "supporting and encouraging" the "violent and unconstitutional" action.

Foot said the uproar was an understandable spontaneous reaction to the government trying "to smuggle through at the very last gasp of the parliamentary session something they should have presented openly."

By even the rather boisterous standards of the House of Commons, where legislators routinely heckle and try to shout down opposing speakers, it was a strikingly chaotic scene.

But it was only the latest in a series of unsettling political developments and signs of growing dissent here as Britain's severe economic recession grows worse and Thatcher's austere monetarist policies bite more deeply.

The decision to increase public housing rents by more than 30 percent, which government officials said will now be made next week, affects one family in three in Britain. And it comes on top of a freeze on construction and renovation of government housing throughout the country, which will increase already long waiting lists.

Thatcher's government also has decided to limit government pay increases to 6 percent, only a fraction of the current inflation rate. Larger wage increases must be financed by job cuts.

The nation's firefighters, the first group of workers caught in the 6 percent squeeze, have begun a work-to-rule protest. They also have threatened to escalate the protest, until they receive a 15 percent pay raise promised them in negotiations with the former Labor government before Thatcher came to power last year. Much larger civil service unions are threatening crippling strikes this winter.

Thatcher's Cabinet is still embroiled in difficult negotiations on other ways to reduce government spending, including previously exempt areas such as defense. For the first time in four years, the British military chiefs of staff this week exercised their right to make a personal protest at 10 Downing St. to argue that any cut in previously planned defense spending would erode Britain's commitment to the North Atlantic Treaty Organization to increase annual military expenditures by 3 percent above inflation.

Defense is not likely to bear as large a share of the cuts as Thatcher's advisers originally sought. Welfare state programs and services such as housing and education are expected to continue to suffer the brunt of the cuts, increasing the unpopularity of Thatcher's harsh economic policies.

Britain's record postwar unemployment rate of more than 8 percent already has hurt Thatcher in new public opinion polls. The surveys place her well behind Foot in voter preference, even though Foot just became Labor leader this week and is known for radically left-wing views on many issues.

While unemployment continues to rise, industrial production continues to plummet in a recession forecasters expect to last until 1982 or 1983.

Many industrialists have become much more outspoken in their criticism of Thatcher for not beginning to ease the squeeze on private industry by reducing the minimum lending rate, which is still at 16 percent, and taking other steps to lower the inflated value of the pound sterling, which has made British exports much less competitive.

At the annual conference of the Confederation of British Industries earlier this week, speaker after speaker agreed with Thatcher's basic strategy but pleaded for relief for business in specific policies before there was no industry left to rebuild when the recession finally ends.

"There is a great danger that the damage will be substantial," said Vicount Caldecott, chairman of the Delta Metal Co. "Markets will be lost forever, we will still have high unemployment. There will be a great social cost."

A growing number of Conservative legislators from hard-hit industrial constituencies have been joining businessmen in publicly urging the government to become more flexible in its policies. Referring to the impact of interest rates the government has kept high to try to tighten up the money supply, senior Conservative member Geoffrey Rippon asked in the House of Commons, "are we not in danger of creating a society in which moneylending is the only profitable venture?"

"We have to make a determined and sustained effort to slow down and then reverse the growth in unemployment," a Thatcher Cabinet member, Deputy Foreign Minister Sir Ian Gilmour warned in a guarded but clearly critical speech on economic policy to the Cambridge University Conservative Association.

But Thatcher once again warned this week in a major speech at the annual banquet for financiers hosted by the lord mayor of London at the historic Guildhall that more sacrifices are needed before improvements can be made.

"We now have no alternative," she said, "but to accept a reduction in the country's standard of living if investment and employment are to recover."

"The worst betrayal the British people could suffer at the hands of this government," she said, "would be for us to seek a little more popularity now by sacrificing all hope of future stability and prosperity. That is not our way."