Millions of workers to enjoy more rights under 'gig economy' shake-up
Millions more workers will be given the right to holiday and sick pay following a review into modern employment practices.
Employees in the so-called 'gig economy', including agency workers and those on zero-hour contracts, will also be given the right to a payslip for the first time.
The plans come in response to a review led by former Tony Blair adviser Matthew Taylor, which looked at how to improve the conditions of workers at firms such as Uber and Deliveroo.
Firms which fail to pay employment tribunal fines will also be named and shamed under the 'Good Work' shake-up.
Theresa May said the changes offer "tangible progress" in her quest to improve the rights of British workers as the country prepares to leave the European Union.
But union leaders said the proposals did not go far enough and amounted to "trying to put out a forest fire with a water pistol".
Matthew Taylor's report, which was published last year, said that Britain's flexible workforce was good for the country, but that employees needed greater protection from unscrupulous bosses.
The Government's long-awaited response includes a list of rights which employees should demand on day one in a new job.
They include holiday and sick pay, a payslip for all staff, including those on casual and zero-hour contracts and the right for all workers to request a more stable contract are among plans.
They also include a crackdown on unpaid interns doing the job of a paid employee, and increasing employment tribunal fines for employers “showing malice, spite or gross oversight" to £20,000 - with higher fines for previous offenders.
The Government will also launch a consultation on making it easier for both workers and businesses to understand whether someone is an employee, worker or self-employed - and which rights and tax obligations apply to them.
Ministers will consider repealing laws which allow agencies to employ workers on cheaper rates, while the Low Pay Commission will be asked to consider higher minimum wage rates for workers on zero-hour contracts.
Elsewhere, there will be greater clarity of “working time” for flexible workers who find jobs through apps or online so they know when they should be being paid.
And 1.2 million agency workers will be handed a “clear breakdown” of who pays them and their earnings.
Mrs May said: "We recognise the world of work is changing and we have to make sure we have the right structures in place to reflect those changes, enhancing the UK’s position as one of the best places in the world to do business.
"We are proud to have record levels of employment in this country but we must also ensure that workers’ rights are always upheld.
"Our response to this report will mean tangible progress towards that goal as we build an economy that works for everyone."
Matthew Taylor gave the Government response a cautious welcome.
"There is much more to be done to make good work for all a realistic goal, but the Government response to my review is substantive and comprehensive," he said. "It will make a difference to the lives of the most vulnerable workers and that is what matters.
"On important issues, including pay for variable hours workers, employment status and representation of workers I welcome the direction indicated, but there is more work to be done to encourage the Government to be bold in living up to its commitment to good work for all."
But trade unions reacted with dismay to the Government's recommendations.
Tim Roache, general secretary of the GMB, said: "This report looks like a consummate guide to tinkering around the edges - like trying to put out a forest fire with a water pistol.
"If the Government is serious about making life better for working people, giving workers the right to request that their bosses stop paying them poorly or treating them badly is an unfunny joke.
"These are weak proposals, from a weak Government that has promised much but delivered little for workers."
Unison general secretary Dave Prentis said: "The Government’s Good Work plan looks set to fall at the first hurdle. It’s no good, it won’t work and it isn’t a plan.
“Britain’s worst employers need to be dragged kicking and screaming into the 21st century, but sadly this response won’t do that."