The continuing rapid rise of unemployment throughout Western Europe was dramatized this week in hard-hit Britain, where the official jobless total surpassed the politically sensitive level of 3 million for the first time.

A record 3,070,621 Britons--12.7 percent of the work force--are currently without jobs as the country struggles to recover from its worst recession in half a century. Registered unemployment during the 1930s Depression here peaked below 2.9 million in 1932, although that represented 22 percent of a smaller working population.

Britain's jobless total is the largest in Western Europe, where an unprecedented postwar increase in unemployment caused by recession and saturation of the labor market following a 1960s baby boom has become a pressing economic, social and political problem. Only Belgium and Spain, with smaller populations, have higher unemployment rates, with 14.6 percent and 13.6 percent, respectively.

The unemployment rate in France and Italy, each with 2 million out of work, is around 10 percent. The number of jobless in West Germany has doubled in the past year to 1.7 million, or 7.3 percent of the work force there. This compares with the near postwar record unemployment rate of 8.9 percent in the United States.

In Britain, the new unemployment figures were treated by politicians, business and union leaders, and the news media as a symbol of the nation's economic crisis. Newspaper front pages prominently displaying the 3 million jobless total warned that unemployment is expected to continue increasing this year and may not slacken much during the rest of this decade.

Analyses comparing the present crisis with the Great Depression emphasized the rapidly expanding work forces and structural economic problems of both eras here and elsewhere in Europe. But the political debate focused on the controversial monetarist policies of Prime Minister Margaret Thatcher's Conservative government. Unemployment in Britain has more than doubled since she took office.

Greeted in Parliament after announcement of the new figures by shouts from the opposition benches of "resign" and "shame," Thatcher continued to defend her policies as the best way to cope with the crisis. She said there was "a certain amount of encouraging news" in reported increases in overtime work and job vacancies. Her aides pointed to other signs that the battered British economy is beginning to recover from the worst of the recession.

Thatcher supporters and many business leaders, including critics of some of her policies, recently have emphasized the other side of the unemployment coin. Industries forced by the recession to shed labor--with tens of thousands of workers laid off by giant private and government-owned textile, auto, steel and other firms--have improved their productivity significantly. Workers also have agreed to lower pay raises and called fewer strikes during the past two years.

Industrial production and company profits started to increase at the end of last year, but economic analysts forecast only a modest rise in the gross national product of 1 or 2 percent this year, which means Britain still would be producing significantly less than when Thatcher took office in 1979.

Thatcher remains under pressure from many business leaders and members of her own party in Parliament to approve spending increases in the next government budget to stimulate the economy. Her Cabinet, which has been deeply divided on this question, meets this week to discuss the budget, which will be presented to Parliament early in March.

A growing number of Conservative members of Parliament, who fear they will lose their seats in the next national election because of the Thatcher government's unpopularity in opinion polls, have threatened to vote against the budget if it does not increase spending to create jobs. Political observers expect Thatcher to approve a modest spending increase at most.

The latest figures showed unemployment to be worst outside relatively prosperous southeast England around London, with a 16 percent jobless rate in northern England and Wales, 15 percent in Scotland, and nearly 20 percent in British-ruled Northern Ireland.