Racial disadvantage "is a fact of current British life" that must be eliminated "if it is not to become an endemic, ineradicable disease threatening the very survival of our society," a major, government-commissioned report on last summer's rioting in racially mixed neighborhoods of many English cities warned today.

The government must adopt "a policy of direct, coordinated attack on racial disadvantage," particularly in education and employment, even if it "inevitably means that the ethnic minorities will enjoy for a time a positive discrimination in their favor," High Court Justice Lord Scarman recommended after an inquiry into Britain's worst urban violence in this century.

Much of his 168-page report, awaited here as the British equivalent of the Kerner Commission report on the rioting in U.S. cities during the late 1960s, is devoted to detailed recommendations to Prime Minister Margaret Thatcher's government for improving police-community relations. But Scarman emphasizes that "good policing will be of no avail unless we also tackle and eliminate basic flaws in our society."

Scarman's report concludes that " 'institutionalized racism' does not exist in Britain, but racial disadvantage and its nasty associate, racial discrimination, have not yet been eliminated. They poison minds and attitudes; they are, and so long as they remain, will continue to be, a potent factor of unrest."

He also blamed policing methods, a failure by both police and community leaders to establish better relations with each other, and "complex political, social and economic" problems, including high unemployment, in inner-city areas. Rather than being "race riots" pitting blacks against whites, he argued, the disturbances were antipolice riots by frustrated young blacks joined and sometimes goaded by whites.

But Scarman also emphasized that the many problems he cites as having helped cause "anger and resentment" in young blacks "cannot justify attacks on the police in the streets, arson or riot."

Scarman, a British Law Lord who is the equivalent of a U.S. Supreme Court justice, focused his inquiry on the rioting in the south London neighborhood of Brixton last April that heralded Britain's long summer of urban disorders. But he also based his conclusions and recommendations on evidence he accumulated on the disturbances during nine consecutive days last July in which more than 3,000 people were arrested and l,500 police officers injured in nearly 30 English cities and towns.

Court records for those charged in both April and July rioting in Brixton show that two-thirds were black, most were in their teens or early 20s, and two-thirds, both black and white, were unemployed. Brixton's population is one-third black, and the unemployment rate among its young black adults is estimated at 30 to 50 percent.

About 3 percent of Britain's population nationally is nonwhite. The majority of people referred to as "black" are immigrants from former British colonies in the Caribbean, Africa and Asia and their offspring.