Britain's report on riots - a plan to move four societies back to one

Suddenly, new ideas are being widely debated here to prevent more urban riots - to bring police, racial minorities, and society together. ''All of us carry some of the blame'' for the unprecedented rioting in Britain last summer, said Lord Scarman. The gentle, respected lord justice of appeal has outlined a new national agenda for discussion with his long-awaited report on the Brixton disorders in London April 10-12, 1981.

Scotland Yard is already listening. It has just appointed a new assistant commissioner for training and personnel, Geoffrey Dear, who was promoted over the heads of senior officers specifically to upgrade police training and relations with the community.

The appointment is tacit acknowledgement of a point Lord Scarman makes: Although police were not racist and generally performed well, they ''were partly to blame for the breakdown of community relations'' in Brixton.

''What we have got to get out of this,'' Lord Scarman said after his report had been issued, ''is one, two, three, or four societies back into one society.''

In part, Britain is looking to United States actions after riots in Detroit, Washington D.C., and other cities in the late 1960s. Lord Scarman quotes the late President Johnson:

''The only genuine long-range solution . . . lies in an attack - mounted at every level - upon the conditions that breed dispair and violence . . . ignorance, discrimination, slums, poverty, disease, not enough jobs. We should attack . . . because we are fired by conscience.''

Lord Scarman points to New York City as a place where police have tried new ideas to improve new contacts with schools, youth clubs, unemployment officers, and elsewhere.

Britain is proud of the image of its police: stern but fair, firm but courteous, unarmed and low key. But the task today is to adjust this traditional police image to the demands of inner cities, which teem with black and white youths who are thrown out of work by recession, who are suspicious of all authority, and who resent poor housing and the lack of places to play sports and to relax.

el3 Lord Scarman has ignited new debate on how police can reestablish personal, human links with their communities. Patrol cars and modern techniques have tended to isolate police from the public. Lord Scarman suggests more foot patrols: They do not ''have a significant effect on the volume of crime,'' but they do ''reduce people's fear of crime.''

Brixton is a run-down city area of London, almost 40 percent of which is West Indian. For three successive nights in April 1981, hundreds of young people attacked police with a ferocity that Britain had not seen before. No one was killed, but on one Saturday evening alone 279 police and at least 45 members of the public were injured, many police and other vehicles were damaged or destroyed, and 28 buildings set on fire. Many buildings were gutted. Widespread looting broke out.

Lord Scarman now believes that subsequent riots in Toxteth, Liverpool, were even more serious. Brixton remains an outgoing area; Toxteth is a ghetto, where blacks are cut off from the rest of the city. The Toxteth community, Lord Scarman told newsmen, must mix with the rest of Liverpool.

London Police Commissioner Sir David McNee has welcome the constructive tone of Lord Scarman's criticisms. He has already begun new training schemes for recruits. Among the issues he must face, and which Lord Scarman spotlights:

* British police need more community-relations instruction and experience.

* Young recruits need more training. Now they get only 15 weeks, which Lord Scarman says is less than in many other countries. He recommends it be lengthened to six months.

* ''Vigorous'' action is needed to find and train black police officers.