The Labour Party on Saturday poured scorn on a Conservative election pledge to impose a new levy on banks' borrowing to pay for a tax break to reward couples who get married.

The Conservatives, who have a small lead in the polls ahead of a May 6 election, said it would send a signal that they value marriage. Labour called it a political gesture that would penalise some families.

The proposal touches on the Conservatives' central campaign pledge to fix what they describe as "Broken Britain," a place of family breakdown, crime and welfare dependency.

Prime Minister Gordon Brown, seeking an historic fourth consecutive election victory, said the Conservatives would cut school budgets, tax breaks for middle class families and state-assisted child savings accounts.

"I am a great believer in marriage," Brown said. "But what this is giving a little with one hand and taking away a lot with another."

Work and Pensions Secretary Yvette Cooper said the idea was "unfair, irresponsible (and) out of date," while Britain's third party, the Liberal Democrats, called it "patronising drivel."

At the end of the first week of the election campaign, a poll in the Daily Mail newspaper put the Conservatives in the lead on 37 percent, with Labour on 27 and the LibDems on 22.

That would give the Conservatives a slim 20-seat majority in the new 650-seat lower chamber, narrowly avoiding the markets' fears of a "hung parliament," where no one party has overall control. Most recent polls have pointed to an inconclusive victory.

If elected, the Conservatives said they would pay for the measure through a new levy on banks' wholesale borrowing that would raise 1 billion pounds.

Half would be used to cut government borrowing and the rest would go to married couples. Basic rate taxpayers earning less than 44,000 pounds would receive 150 pounds a year, as long as their spouse doesn't work.

"It is a very powerful signal that we do value marriage as a very important form of commitment," Conservative universities and skills spokesman David Willetts told the BBC.

The marriage plan moved the focus of the campaign away from Labour proposals to raise the payroll tax, a topic that has dominated the debate since Brown called the election on Tuesday.

The parties are divided on how to reduce the record public deficit, forecast to exceed 11 percent of GDP in the 2010/11 fiscal year. The Conservatives are pushing for faster and deeper cuts in public spending. Labour says that would damage the fragile recovery from the worst recession since World War Two.

(Additional reporting by Adrian Croft)