The number of workers without guaranteed hours or basic employment rights has soared by more than 660,000 in the past five years, a study reveals.
The TUC said its research showed those affected by the jump in so-called insecure work included waiters, care workers and education staff.
The rise of 27% is being driven mainly by traditional industries rather than the newer tech sectors, according to the report.
Restaurant and pub waiters make up a fifth of the increase, while there has also been a big rise in education and care home workers facing insecurity, said the TUC.
General Secretary Frances O’Grady said: “Insecurity at work is becoming the new normal for too many workers. It’s happening across new and old industries, with workers forced onto shady contracts, whether they’re Uber drivers, bar staff or teaching assistants.
“People need jobs they can live on and build a life around, but if you don’t how much work you will have from one day to the next, making ends meet is a nightmare.
“How is a working parent supposed to plan childcare when they don’t know the hours they’ll be working? And how can it be right that in 2017, workers are at the mercy of bad bosses who can just take away all their hours or throw them off the job with no notice?
“The rules that protect workers need to be dragged into the 21st Century.”
The TUC said workers on zero-hours, casual, agency or temporary contracts missed out on protections such as sick pay and found their wages could fluctuate without warning.
A league table of industries where workers are most likely to face insecurity is headed by arts and entertainment, followed by domestic work, freight transport and clothes manufacturing.
The TUC estimated that more than three million people now work in insecure jobs, up from 2.4 million in 2011, representing one in 10 UK employees.