LONDON - Prime Minister Gordon Brown vowed to address concerns over declining living standards after his Labor Party lost a parliamentary seat that it had held since World War II.

It was the second major electoral setback this month for Brown.

Conservative Edward Timpson won 49 percent of the vote in Crewe and Nantwich, compared with 31 percent for Labor's Tamsin Dunwoody.

The election, whose results were announced yesterday, was triggered by the death of Dunwoody's mother, Gwyneth, a member of Parliament, who received 49 percent of the vote in 2005.

Labor lawmakers said the defeat puts many of their own seats at risk in the next national election, which must be held no later than mid-2010. Polls show rising consumer prices and the slowing economy are now the biggest concerns among U.K. voters.

"The message from the voters is clear and unequivocal, that people want us to address the very real challenges," Brown told reporters in London. "The task ahead is to take the British economy through what are very difficult times."

The result was a milestone for the Conservatives, which last won a seat from Labor in a special election in 1978, the year before Margaret Thatcher took office.

"It is very significant for the Conservatives," Andrew Hawkins, chief executive officer of polling firm ComRes, said. Labor has "dropped off a cliff popularity-wise."

Brown went into the election facing mounting criticism of his leadership since taking over from Tony Blair in June - after a defeat in local authority elections three weeks ago and a tax change that left 5.3 million of the poorest households worse off.

Voters in Crewe spurned a last-minute push by Labor to win their support.

On May 13, Chancellor of the Exchequer Alistair Darling announced a $5.3 billion emergency tax cut to compensate those who lost out when he abolished the 10 percent starting rate of tax.

"It may just be that after a decade in power, people are getting a bit more tired of Labor, and that's their biggest danger: voter fatigue," Rick Nye, a political analyst at polling firm Populus Ltd., said.

The Conservatives increased their share of the vote by 16 percentage points from 33 percent in 2005, taking support from both Labor and the Liberal Democrats, who saw their share slip to 15 percent from 19 percent.

The Conservative win suggests the party is now capable of winning seats in Labor heartlands.

Labor has 351 representatives and a 65-seat majority in the 646-seat House of Commons. Recent opinion polls show Labor trails the Conservatives, led by David Cameron, 41, by as much as 26 percentage points.

"It was a fantastic result, but there won't be one hint of triumphalism or one hint of complacency from the Conservative Party," Cameron said in Crewe. "Thousands of people have voted for us for the first time, put their trust in us. I want to build the biggest coalition for change in our country that we can."

Crewe, near Manchester, made its name as a locomotive workshop during the heyday of steam railways in the 19th and early 20th centuries.

It has voted for Labor since 1945. The town was combined with neighboring Nantwich, a Conservative supporting area, into an electoral district in 1983.