BRITAIN'S INFLATION and interest rates are soaring while its productivity and standard of living continue to slide. Its post office and public transportation system, once models of efficiency, have deteriorated. Its cities are rundown and dirty; its people avoid work.

Assaults in pubs, murders in discos, and weekend rampages by motorcycle gangs and soccer fans have become commonplace forms of youthful violence. The police, in a break with tradition, are arming. Conflicts between labor and management, lower and upper classes, young and old, black and white, and left and right permeate the society.

Citing in his introduction a general mood of malaise and stagnation on the one hand, and on the other the growth of unrest, discontent and disorder, editor Isaac Kramnick, a Cornell University government professor asks the right question: Is Britain drying?

But the jumble of essays he has collected from British politicians and both British and American academics wastes a good opportunity to search intelligently for answers.

The politicians avoid the question. Former Conservative prime minister Edward Heath, keeping himself a politically attractive candidate to replace Margaret Thatcher if she makes too big a mess of things, refuses to admit there is even a problem. Former Labor minister Barbara Castle, defending her party's recent years in power, chooses to dwell instead on the simultaneous economic decline of the United States.

The academicians waste too much of their space arguing over fine historical points, advancing eccentric these and engaging in pedantic games in often unintelligible social science jargon. Foreign policy depends on power, boldly declares Cornell professor Richard Rosecrance in a tedious review of Britain's post-colonial decline as a world power. Another Cornell professor, Milton J. Esman, offers a strained center-periphery paradigm to explain the rise of regionalism and ancient nationalism in Scotland, Wales and northern England. Ira Katznelson of the University of Chicago, in perhaps the most obscure and irrelevant contribution, suggests halfheartedly, an rhaps the most obscure and irrelevant contribution, suggests halfheartedly, an Americanization of British politics with a series of evidential non sequiters from other scholars' studies.

Here and there, a careful and determined reader can find valuable insights, not the least of them in Kramnicks' introduction, one of the few incisive, readable parts of his book. He points to public opinion polls that show Britons to be remarkably contented with their lot, and to arguments by some observers that Britain is once again in the vanguard of progress, setting forth new and innovative patterns of life for a post -- industrial age of greater leisure and less economic growth.But Kramnick asks whether this complacency is not itself a most glaring symptom of Britain's very crisis and decline.

Stephen Blank, an American researcher into corporate, union and political behavior, raises good questions about the failure of British governments to engage in effective long -- term planning, about their leaders' confusion over the future of Britain's welfare state. And about conflicts within the powerful British union movement that may overshadow its conflicts with management and government.

University of Maryland professor Robin Marris, formerly a scholar and teacher at Cambridge University, zeros in on Britain's management malaise, which he blames on the well-educated upper classes distaste for and avoidance of training for and careers in business management.

Ralph Miliband, a British academic currently teaching at Bradeis University, explores what he calls "desubordination" by people frustrated with remaining at the bottom of the heap in British society: the people who work in factories, mines, offices, shops, schools, hospitals. Because neither Labor nor Conservative goverments have taken their grievances seriously, according to Miliband, they have become more alienated and determined to block prgress. He predicts that the period ahead, whichever government is in office, appears destined to be marked by much greater social tension, class conflict and political instability than has been the case for many a year.

It is a pity that Kramnick did not take the trouble to encourage fuller development of such provocative essays and weed out the lazy, self-justifying and pretentious contributions that crowd the others. This book bears the earmarks of publishor -- perish academic expediency. The British disease, in part because its symptoms are now appearing in the United States, deserves more serious study.