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People on zero-hour contracts are more than twice as likely to work night shifts, and are paid a third less an hour than other workers, the TUC says.

After polling 3,287 workers - 300 of them zero-hour staff - it concluded the "exploitative" system should be banned.

It says the flexibility such contracts offer are only "good for employers".

But the government said a ban would "impact more people than it would help", arguing zero-hours worked well for students, carers and retirees.

"They provide flexibility for both employers and individuals, such as carers, students, or retirees," a business department spokesman added.

TUC general secretary Frances O'Grady said "the vast majority" of people on zero-hours contracts "want out".

"Zero-hours workers regularly work through the night for low pay, putting their health at risk. And many face the constant uncertainty of not knowing when their next shift will come," she added.

Flexibility or insecurity?

The TUC's research is likely to reignite the debate over zero-hour contracts.

While the casual employment contracts don't oblige employers to provide a minimum number of working hours, they don't oblige employees to accept any of the hours offered by their employer either.

Workers on zero-hours contracts are still entitled to statutory annual leave and the national minimum wage.

Although such contracts have been controversial, many say they provide flexibility to people such as students, parents and those with other caring responsibilities.

But critics say that zero-hours contracts create insecurity for workers and are used by employers to undercut wages and avoid holiday pay and pension contributions.

The TUC says its research suggests two-thirds of zero-hours workers would prefer jobs with guaranteed hours.

The research also suggests:

The median hourly pay before tax for someone on a zero-hour contract was £7.70 compared to £11.80 for other workers

It found 23% of zero-hour contracts have night work as a usual part of their working pattern, compared to 11% of other workers

The union's research was based on analysing the latest official data on zero-hours contracts.

The data shows there are around 780,000 on such contracts, equivalent to 2.4% of the working population.

People on such contracts are more likely to fall into one or more of four categories - young, part-time, women or in full-time education.