LONDON -- Former Defense Minister Michael Heseltine challenged Prime Minister Margaret Thatcher yesterday for leadership of Britain's Conservative Party and the country, throwing the entire political scene here into turmoil.
He acted less than 24 hours after Mrs. Thatcher was subjected to a devastating attack in the House of Commons by her former deputy, Sir Geoffrey Howe, over her anti-European attitude.
"I am persuaded that I would have a better chance now, a better prospect now, than Mrs. Thatcher of leading the Conservatives into a fourth election victory, thus avoiding the ultimate calamity of a Labor government," Mr. Heseltine said.
For the past year the opposition Labor Party has held a double-digit lead in opinion polls over the Tories, and Mrs. Thatcher's popularity has plummeted as her strident leadership, her negative posture toward Europe and her handling of the economy -- now in recession -- have come under increasing fire.
Her anti-European policies were the catalyst of the crisis but were thought to be unlikely to be the decisive factor in the vote on her future.
The election, to be held Tuesday, will involve the 372 Tory members of Parliament. They are to decide which candidate has the best chance of ensuring their own re-election in the next general election, to be called by June 1992.
They will judge the difference in styles between Mrs. Thatcher's dominating leadership and Mr. Heseltine's inclination to seek consensus, observers said. They also will weigh the varying emphases of the two candidates on policies ranging from the economy to the environment.
They also must decide whether Mrs. Thatcher can now continue to lead the party without inflicting the permanent image of disunity on it.
One Thatcher insider admitted, "Leadership challenges are damaging politically, especially in a country which has so far put so much emphasis on unity in a political party."
Under the voting rules, Mrs. Thatcher, 65, will need 214 votes to win outright and continue her 15 years as Conservative Party leader and her 11 years as prime minister. Mr. Heseltine, 57, said he decided to run after receiving pledges of support from more than 100 MPs.
The campaign will not be conducted openly but will be fought in the parliamentary corridors of power, with each side twisting as many arms as possible.
If neither candidate finished with a 15 percent majority over the other on the first ballot, a second-round vote would be held a week later, and other candidates could enter. In a fragmented field, it could take several votes for a winner to emerge.