LONDON, OCT. 2 -- Labor Party leader Neil Kinnock today pledged better management of this country's beleaguered economy, school system and health services if he is elected prime minister.

In a passionate keynote speech at his opposition party's annual conference in Blackpool, Kinnock won loud applause when he lashed out at Prime Minister Margaret Thatcher for Britain's double-digit interest and inflation rates and other economic woes.

But Kinnock's main purpose today and all this week at this carefully orchestrated media event is not so much to bash Thatcher as to offer a soothing, alternative vision that middle-of-the-road voters -- who for a decade have rejected Labor as too incompetent or radical or both -- can feel comfortable with and endorse.

"The overall picture" Labor is aiming for, the influential Financial Times said in an editorial, "is of an opposition that promises to do very little and hurt no one."

Recent polls suggest that the British public, while critical of Thatcher's economic record, remains skeptical about Kinnock as an alternative. Several surveys last weekend showed the Conservatives inching back up to 6 to 10 percentage points behind Labor in voter support -- a major improvement over the 20- to 25-point gap of last spring.

Analysts say the margin has narrowed because Thatcher has managed to look tough and prime ministerial during the Persian Gulf crisis and because Kinnock has yet to persuade voters that Labor would do a better job of economic management. Thatcher had hoped to call a new election next year, but with the economy in a tailspin, Conservative politicians say she may wait until the last minute -- spring of 1992.

In the past, Labor's annual party conferences were often untidy, leftist-dominated political bloodbaths -- cynics called one year's radical party manifesto "the longest suicide note in history."

Kinnock gradually has throttled Labor's left by installing his own political lieutenants in key posts and by dismantling the old socialist-oriented party platform. One measure of his success has been the way he has transformed the annual conference into a stage-managed lovefest similar to that of Thatcher's Conservatives.

Still, the seams occasionally show through. Six members of Kinnock's own "shadow cabinet" voted against him and supported an executive resolution that would commit Labor to about $12 billion in defense cuts. Nonetheless, Kinnock and Labor's leadership have gotten most of what they wanted, including measures that would cut the voting power that trade unions hold inside the party.

In his speech today, Kinnock said a Labor government would cut Britain's 15 percent annual interest rate by one point, institute tough credit controls and join the European exchange-rate mechanism as quickly as possible. He also promised to revamp the country's troubled school system and to spend more money on science, research and transportation.

He also repeated his suppport for President Bush's deployment of troops in the gulf, although he pleaded that economic sanctions be given "the longest possible time" to work before military force is contemplated.