London — Prime Minister Margaret Thatcher has comfortably resisted opposition efforts to press her toward a policy of economic sanctions against South Africa. But a House of Commons debate on the issue held Tuesday, followed by a vote, exposed serious divisions in her ruling Conservative Party on how to respond to Pretoria's tough, new law-and-order policies.
In a vote on a Labour Party motion urging the government to take economic measures, Mrs. Thatcher held a comfortable majority of 125. There were, however, 15 Conservative abstentions, and the prime minister and Sir Geoffrey Howe, the foreign secretary, had to battle hard to prevent other Tories from supporting sanctions.
A former foreign secretary, Francis Pym, argued that Britain had a duty to take the lead in pursuing a sanctions policy, because South Africa's latest actions indicated that the Pretoria government was unwilling to listen to reason.
Peter Temple Smith, an outspoken Conservative Member of Parliament and vice-chairman of the party's Foreign Affairs Committee, also abstained. ``I believe the mood of the House of Commons as a whole has changed on the sanctions issue,'' he said. ``I now personally believe that sanctions -- however unpalatable they may be -- are the only line of approach open to us.''
Thatcher showed little sign of worry that her policy is being challenged from within her own party. But British government insiders are certain that the Prime Minister's Cabinet is split over the issue of sanctions. A minority of ministers are convinced that the Thatcher government will not be able to resist the pressures -- domestic and international -- building up on it to take decisive action against South Africa.
At the height of Tuesday's debate, Labour opposition leader Neil Kinnock said Thatcher's position was ``morally and logically unsustainable.'' He said her belief that a solution could be negotiated without the prior imposition of sanctions was either ``simple-minded delusion or supine appeasement.''
There are indications, however, that Thatcher may be prepared to edge toward some sort of compromise on the sanction issue. News reports last weekend said that government officials were compiling a list of possible economic measures, including an end to air links between South Africa and Britain and a ban on imports of South African farm products.
Thatcher's advisers are telling her that members of the Commonwealth -- a group composed of former and present British colonies -- will demand that Britain join in a policy of large-scale sanctions at a special summit meeting in London later this summer. The meeting follows the release last week of a report urging a hard line approach toward South Africa.
The prime minister will be attending a summit meeting of the European Community in The Hague next week, at which she is expected to be asked to justify her opposition to sanctions.