JOHN MAJOR'S future as prime minister is likely to be decided at local council elections to be held in London and other centers a month from now.
If his party's candidates do badly in nationwide polls on May 5, scores of Conservative parliamentarians say they are likely to back a challenge to his leadership.
Officials of the Conservative Party, which has ruled the country at the national level since 1979, privately concede that the local election results in London could be crucial. If enough voters in the British capital switch to rival parties in the 32 boroughs where polling will take place, the days of the man who succeeded Margaret Thatcher in 1990 probably will be numbered.
Four London boroughs, including Westminster, where Parliament resides, currently are held by the Conservatives with slender majorities. An opinion poll conducted by the opposition Labour Party on April 3 suggested that the Conservatives were in for a drubbing in London and many other centers.
The poll put Labour 20 percentage points ahead of the Conservatives, and suggested that in several areas the centrist Liberal Democrats would push the Conservatives into third place.
John Smith, the Labour Party leader, is forecasting a massive swing against the Conservatives in London. He says the vote will be a referendum on Mr. Major's leadership and on the government's stewardship during 15 years continuously in power.
The Conservatives currently hold 12 of the capital's boroughs against Labour's 15 and the Liberal Democrats' three. Two others are under divided control.
Four years ago the Conservatives did well in London local elections, gaining 76 council seats. But the political mood in the capital has clearly changed.
A Conservative councillor in Brent, a key battleground on the outskirts of London, says his party was ``virtually certain'' to lose control of the local council, ``unless there is a miracle.''
The councillor says the main problems for the Conservatives were the prime minister's low standing with voters and the government's decision to impose heavy tax increases nationwide, starting April 6.
Suggestions that Major could lose his job if citizens cast protest votes on May 5 have brought him out fighting. Opening the party's campaign on April 6, he told supporters that he proposed to ``lead from the front'' and take personal responsibility for the outcome.
In pursuit of his high-risk strategy, the prime minister plans to stage a series of regional meet-the-people tours, using the methods that helped him to win the April 1992 general election.
In 1992, Major literally grabbed a soap box and used it as his platform as he stomped the country, meeting and speaking to as many voters as possible.
The outcome in 1992 was an embarrassment to pollsters who had forecast a Labour victory.
Apart from London, votes will be held in 36 metropolitan districts and 130 shire, or county, districts. Nearly 5,000 council seats are at stake, and 30 million Britons will be entitled to vote.
The high stakes involved have led Sir Norman Fowler, the Conservative Party chairman, to order a campaign that one of his aides said would be ``like a mini-general election.''
The aide pointed out that a month after the local polls, British voters will be asked to elect members of the European Parliament. In addition, five parliamentary by-elections are to be held in May and June.
This accumulation of electoral contests comes at a time when Major's standing with his own parliamentary backbenchers is at an all-time low. Polls of Conservative members of parliament carried out late last month after Major backed down in a contest with other members of the European Union over voting rights, showed about half of them were critical of his leadership.
Many of the parliamentarians say they fear the adverse impact on their party of the new tax rises, which on average will cost wage-earners an extra 500 pounds ($735) a year.