A "staggering" 5.5 million workers could be on zero hours contracts, according to a study of 5,000 members of the Unite union.
A study found more than one in five Unite members were on zero hours contracts - five times higher than prior estimates - with half of respondents in the 16-30 category.
Unite general secretary Len McCluskey said the research suggests a "growing sub class" of insecure, low paid employment, with only one in seven wanting to remain on the contracts.
The results of the study by social survey company Mass1 came as employment rights will be debated on the first day of the TUC congress in Bournemouth today.
More top news
The 20-year-old was found fatally wounded on Roth Walk, near Finsbury Park, north London at around 3am on Saturday, Scotland Yard said.
Daniel Cowell has been jailed for five years and four months after ramming a police patrol car with a stolen transit van.
The OPCW have left the site of the suspected chemical weapons attack in Douma and should have results in about a week, ITV News understands.