British Prime Minister Margaret Thatcher's iron-clad opposition to Commonwealth sanctions against South Africa is increasingly likely to break the group's tradition of decisionmaking by consensus, diplomats say. They said there was a growing belief among Commonwealth leaders that the group's summit would ultimately draft a final communiqu'e calling for sanctions against South Africa -- but with Britain dissenting on that single issue.
Such a move would mark a radical departure from the 49-member organization's tradition of consensus.
Unshaken by both formal and informal pleadings from her fellow leaders, Mrs. Thatcher has lived up to a reputation for intransigence, standing fast against any threat of sanctions to force the white-minority South African government to change its policies of racial separation.
From its start with formal sessions last week, the meeting has been marked by intensive efforts to come up with a way to convince Britain to change its mind on the issue.
Britain has consistently objected to economic sanctions, saying they would harm South African blacks and stiffen the Pretoria government's resistance to reform of apartheid.
The latest bid for compromise came yesterday at an informal weekend retreat when Thatcher was visited by Prime Ministers Rajiv Gandhi of India and Brian Mulroney of Canada.
But diplomatic sources said that effort, too, was of no avail. Although Thatcher agreed to attend a meeting of all leaders today, they predicted a compromise was out of reach.
Thatcher spent most of yesterday in the isolation of her beach-front home on nearby Lyford Key.
``She's not knocking on many people's doors,'' a British official said.
But in the afternoon she received Gandhi and Mulroney, part of a four-member committee trying to find common ground between Britain and other Commonwealth nations over sanctions.
``This is a difficult problem, and as in all negotiations time is of the essence,'' a British official said.