Britain’s booming gig economy has more than doubled in size over the past three years and now accounts for 4.7 million workers, according to a report laying bare the increasingly precarious nature of employment.

In a sign of the rapid shift in the modern jobs market as many as one in 10 working-age adults now work on gig economy platforms, up from one in 20 as recently as 2016, finds the study from the TUC and academics at the University of Hertfordshire.

Revealing how a boom in digital platforms, such as Uber and Deliveroo, has sparked a revolution in the world of work, the report warns that workers’ rights have failed to keep pace with the dismantling of the traditional nine-to-five working week for growing numbers of people.

Frances O’Grady, general secretary of the Trades Union Congress, said the explosion of the gig economy showed that working people ran the risk of battling to make ends meet. “The world of work is changing fast and working people don’t have the protection they need. Huge numbers are being forced to take on casual and insecure platform work – often on top of other jobs. But as we’ve seen with Uber too often these workers are denied their rights and are treated like disposable labour.”

This latest snapshot of the gig economy in Britain, part of a broader study spanning 13 European economies including Italy, Spain and Sweden, comes from a poll of 2,235 UK residents, aged 16 to 75, by the University of Hertfordshire, with fieldwork and data collection from Ipsos Mori.

Based on the responses, it was found the number of working-age adults who had worked for an online platform at least once a week had more than doubled, from 4.7% (2.3 million workers) three years ago, to 9.6%, (4.7 million) today.

The survey found, that amid the proliferation of high-tech startups and Silicon valley firms, even greater numbers of people had worked using a digital platform at some point in their lives.

Up to one in seven working-age adults – about 7.5 million people – have worked via a gig economy platform at some point.

Overall employment in Britain has reached a record high of 32.75 million, following a boom in job creation since the 2008 financial crisis. However, economists believe the jobs market has become increasingly precarious for some people, putting pressure on living standards. Poverty while in work has increased, alongside the the use of food banks.

In a sign of the intense pressure facing households across the UK, average wages after inflation remain below the level recorded before the financial crisis.

David Blanchflower, a former member of the Bank of England’s rate-setting monetary policy committee, who recently published a book on the rise of precarious work, said: “The gig economy isn’t necessarily bad but it does show the changing nature of work – you also have to look at rising self employment and short-term contracts in traditional jobs.

“The fear of unemployment has picked up in the UK. People got scared senseless by what happened in the great recession. Real wages have been held down and [people are] concerned that their jobs will be replaced.”

John McDonnell, the shadow chancellor, said: “While the Tory leadership hopefuls slug it out over tax cuts for the wealthy this is the reality of insecure and casualised work for so many in the country.”

The Office for National Statistics estimated the size of the gig economy workforce in 2017 to be 4.4% of the population.

The work from the TUC and Hertfordshire University takes a slightly broader definition of platform work, taking account of paid tasks found via a website or app. It does not include letting property on platforms such as Airbnb, or buying and selling goods online.

According to the study, younger workers are most likely to work via platforms, with nearly two-thirds of those working once a week being aged between 16 and 34. Men are more likely than women to undertake such work, while most people use more than one platform to earn a living.

The findings follow growing numbers of legal battles fought between gig economy companies and trades unions over workers’ rights.

The courier company Hermes this year agreed to offer drivers guaranteed minimum wages and holiday pay following a case brought by the GMB union.

The government also promised to boost workers rights after a landmark review of the gig economy, ordered by Theresa May, called for greater protection, including the right for workers to request full-time contracts. Unions and Labour warned the measures did not go far enough.

Progress implementing the reforms has however been slow with the government bogged down by Brexit.

Matthew Taylor, chief executive of the RSA thinktank, said the labour market had changed cmore quickly than the reaction of policymakers since his review in 2017.

He said that the government had already made a clear commitment to improving the work quality and rights of all workers, now the challenge for the next prime minister was “to take this agenda and run faster with it”.

Rachel Reeves, the Labour chair of the Commons business committee, said: “The government has been far to slow in tackling the fallout from the gig economy, which too often leaves workers exploited and victim to low pay and insecure work.”