Business Secretary Vince Cable will on Monday use his speech at the Liberal Democrat party conference in Glasgow to promise an end to the "abuse" of zero-hour contracts.

Cable will vow to build an economy that is "fairer for everyone" through legislation to crackdown on the misuse of flexible contracts and through the targeting of "rogue" company directors.

"It is clear that there are abuses in the system, especially around the issue of exclusivity which some employers are demanding from workers on these contracts," he will say, according to extracts of his speech released to the press.

"I am determined to make sure people are paid and treated fairly, while helping to keep people employed in these delicate economic times."

The Office for National Statistics estimates that around 250,000 workers are on such contracts, which offer no guarantee of work.

He will also announce plans to introduce laws making it easier to prosecute fraudulent or reckless directors.

But Cable's speech was overshadowed by his refusal to back party leader Nick Clegg's attempt to quell efforts by the party's left wing to urge the government to ease its austerity programme.

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