Prime Minister Margaret Thatcher's top political strategists will be spending the next week or two trying to determine whether the ''Parkinson affair'' has done permanent damage to her government.
As Parliament prepares to reassemble after its summer break, Mrs. Thatcher's opponents are hopeful that her credibility and public confidence have been undermined by the forced resignation of one of her closest political colleagues.
Cecil Parkinson, secretary of trade and industry and former Conservative Party chairman, had no option but to quit the Cabinet after a former mistress who is expecting his child told newspapers her side of their relationship.
The statement by Sara Keays came during the Tory Party's annual conference at Blackpool. It caught Mrs. Thatcher off balance.
In a fighting speech, the prime minister insisted her government's program of public spending and tax cuts would go ahead, but the Labour Party opposition under its new leader, Neil Kinnock, charged that Mrs. Thatcher's reputation for supposed infallibility was shattered and that the government was in disarray.
Topping Labour's criticisms was the prime minister's handling of the Parkinson affair. Despite party pressure for him to resign as soon as details of the affair with Miss Keays were made public, Mrs. Thatcher stood by the minister whose career she had nurtured. In the end, Parkinson had to go, and Mrs. Thatcher's critics accuse her of dithering.
The Tories under Mrs. Thatcher have held out for family values. Their opponents, Mr. Kinnock included, are preparing to make the most of an incident in which personal morality and family cohesion have been central issues.
Mrs. Thatcher hopes the Parkinson affair will blow over, but other storm clouds have been gathering since the huge Tory victory in the June election. The government has not had much success in dispelling them.
In July Tory backbenchers revolted over their salaries, which Mrs. Thatcher wished to limit to a rise of 1 percent.
Then emergency public spending cuts were announced, producing howls of pain from Defense Minister Michael Heseltine.
A parliamentary debate on the death penalty seemed to show the prime minister unwilling to take a stand and unaware of the feelings among her own supporters in Parliament.
In September the health secretary, Norman Fowler, announced manpower cuts in the national health service, sparking a revolt in some sections of the party.
Even some of Mrs. Thatcher's supporters began saying the government was adrift with no central strategy. They focused on what many see as a contradiction: a pledge to cut taxes without clear indications as to where further public spending reductions might be possible.
The Parkinson affair broke just as Mrs. Thatcher was trying to wrestle with these issues. Her speech to the party conference, usually a triumphal affair, showed the prime minister under strain.
But she moved swiftly to repair some of the damage caused by the scandal. She named her trusted employment secretary, Norman Tebbit, to replace Parkinson, thus ensuring the momentum of efforts to pull Britain out of recession.
Mrs. Thatcher is worried by the new lease on life the Labour Party gained by choosing Neil Kinnock as leader. A young and dynamic Welsh orator, Kinnock has moved swiftly to close party ranks.
All the same, he has a major problem: Labour's left wing, though chastened, remains strong. The party is saddled with an image of internal division and attachment to unpopular policies such as unilateral nuclear disarmament.
Mrs. Thatcher's parliamentary opposition is split between the Labour Party and the allied Liberal and Social Democratic parties. With her huge majority in the House of Commons, she is in little apparent danger in the short term.
But it is acknowledged within the Conservatives' central office that since the general election a malaise has begun to afflict the party. Future economic strategy is likely to be the focus of attention.
Mrs. Thatcher is committed to tax cuts and to a further hacking away of what she sees as deadwood in the public sector. But not all her Cabinet colleagues are so attached to these objectives. The so-called ''wets'' say the time has come to move toward the political center, muting her enthusiasm for monetarist solutions.
Mrs. Thatcher's political reputation has rested on her forceful character and her sheer strength and determination as a leader. The Parkinson affair has modified that image somewhat.
On the other hand, until the Falklands crisis, critics note, Mrs. Thatcher was not widely popular. Kinnock is apt to regard her performance during and after the war in the South Atlantic as a momentary political recovery. His aides say Thatcher-ism is reverting to its former position of a narrow, unpopular doctrine with little relevance to contemporary British politics.
The Parkinson affair may turn out to be little more than a blip on the political graph if Mrs. Thatcher sorts out her policy priorities and reasserts her character as leader of the Tories. Her opponents' aim as winter closes in will be to keep her off balance and vulnerable to attack.
One of her sympathizers summed it up: ''Margaret is a conviction politician. If she makes too many errors, her reputation for strength and sound judgment may disappear quickly.''