A Government-ordered review into the employment rights of workers in the gig economy, which calls for better jobs to be created, has been attacked as "feeble."
The review, headed by Matthew Taylor, a former adviser to Tony Blair, recommended a new category of worker called a "dependent contractor", and said there should be "genuine two-way flexibility", giving workers additional protections.
The report by Mr Taylor, the head of the Royal Society of Arts, said low-paid workers should not be "stuck" at the living wage minimum, or face insecurity.
Speaking at its launch in London, Prime Minister Theresa May is expected to promise that the Government will act "to ensure that the interests of employees on traditional contracts, the self-employed and those people working in the 'gig' economy are all properly protected".
But she will insist that Britain must avoid "overbearing regulation", retain flexibility in the labour market and remain "a home to innovation, new ideas and new business models".
Unions and employment lawyers criticised the report, which has taken nine months to produce, for doing little to help the growing number of workers in delivery and taxi firms such as Deliveroo and Uber.
TUC general secretary Frances O'Grady said: "I worry that many gig economy employers will be breathing a sigh of relief this morning.
"From what we've seen, this review is not the game-changer needed to end insecurity and exploitation at work.
"We'd welcome any nuggets of good news, but it doesn't look like the report will shift the balance of power in the modern workplace."
Thompsons Solicitors' chief executive Stephen Cavalier said that the report's recommendations were "feeble and add another layer of unnecessary complexity", adding: "The creation of a new 'dependent contractor' status for gig economy workers would further complicate existing categories of how workers are defined in law.
"What is needed is one category which affords all workers all employment rights from day one of their contracts starting. This new status is unclear and unnecessary."
Mr Taylor said the UK's performance on the quantity of work was strong, adding that now was the time to create better jobs.
"The review calls on the Government to adopt the ambition that all work should be fair and decent with scope for fulfilment and development.
"Despite the impact of the National Living Wage and tax credits, there will always be people who are in work but finding it hard to make ends meet.
"Our social contract with those people should include dignity at work and the realistic scope to progress in the labour market.
"Bad work - insecure, exploitative, controlling – is bad for health and wellbeing, something that generates cost for vulnerable individuals, but also for wider society.
"Improving the quality of work should be an important part of our productivity strategy," he said.
Mr Taylor set out seven "principles for fair and decent work", including a goal of "good work for all", additional protections for workers suffering unfair, one-sided flexibility, stronger incentives for firms to treat workers fairly, and a more proactive approach to workplace health.
Mrs May is expected to say that the Taylor review will inform her efforts to ensure that "the high standards of our best employers become the benchmark against which all employers are judged" and that "as the world of work changes, our practices and laws can properly reflect and accommodate those changes".
And she will add: "While avoiding overbearing regulation, we will make sure people have the rights and protections they need.
"That means building on our high employment rate and low unemployment rate – and continuing to strive for full employment.
"It means retaining the flexibility that people value, and recognising that most employers treat their staff not just fairly but well.
"It means remaining a home to innovation, new ideas and new business models, and recognising the risks and difficulties which those striving to build their own business face – not just on day one, but every day.
"But it also means finding the right balance of rights and responsibilities, flexibilities and protections."
Unite leader Len McCluskey said the recommendations must be matched by effective enforcement of the law, adding: " Without fully resourced enforcement then all we have from Mr Taylor and the Government is a dog that is all bark and no bite."
Tim Roache, GMB general secretary, said: "The recommendations show some laudable aims on the surface - and of course any progress in basic employment rights is welcome - but as a whole it's a disappointing missed opportunity.
"Everyone can pay lip service to wanting good quality, well-paid work but employers could offer that right here and now - they simply choose not to. They won't decide to do so just because they're asked nicely."
Mr McCluskey said: "This review raised the prospect that the scourge of insecure working in this country would be tackled.
"It raised the hope that work would once again pay and there would be no profit in exploitation. It indicated that fairness and dignity would be restored to working life.
"But it has spectacularly failed to deliver on any of these. The seven pillars of Taylor are very wobbly and tumble to rubble under first scrutiny."
The Independent Workers' Union of Great Britain said it had discovered that Greg Marsh, one of the panel members of the Taylor review, was an early investor in Deliveroo.
General secretary Dr Jason Moyer-Lee said: "The idea that a former Deliveroo investor would be one of the people making recommendations on employment rights in the gig economy undermines the entire integrity of this process.
"People should take with a large grain of salt anything they recommend."
A Government spokesman said: "Greg Marsh is clearly an expert in his field and has insight into modern working practices, as well as being a successful entrepreneur.
"Given the importance of considering the business aspect of any proposals, it was right that someone with his experience was involved.
"Prior to his appointment he disclosed his interest to the Cabinet Office and agreed to divest himself of his shares."
Public and Commercial Services union general secretary Mark Serwotka said: "It is no surprise these seven points are so weak and business-friendly given Taylor was commissioned by a Tory government that forced through the Trade Union Act that had at its core the aim of undermining the collective strength of workers.
"If they are representative of the full report, it will fall woefully short of being a serious attempt to improve workers' rights and will offer nothing to the growing army of people exploited on zero-hours contracts and in insecure work, and nothing to the millions living in poverty because of low wages."
Shadow business secretary Rebecca Long-Bailey said: "Put simply, today's Taylor report shows that Theresa May is failing working people across the country.
"If they were serious about workers' rights they are welcome to borrow from Labour's manifesto. Our 20-point plan would truly transform the world of work, providing security, rights and protection for millions of working people.
"There are now 4.5 million people in insecure work, hundreds of thousands not being paid the money owed to them, and hundreds of complaints of employment agency malpractice going uninvestigated."
Neil Carberry, CBI managing director for people and infrastructure, said: "Businesses will be looking to the Taylor review to set out the benefits of the UK's flexible labour market for everyone.
"It's absolutely right to focus on what makes for good work, and firms of all shapes and sizes will find much to agree with in the seven principles of decency and fairness.
"The key now is to find practical ways to deliver both fairness and flexibility, with a focus on employee relations, not just legal reform."