Almost £3 billion of wages and holiday pay are unpaid every year and the figures could be the "tip of the iceberg", a report has found.
Researchers from Middlesex University London also discovered that one in 20 workers do not have paid holidays while one in 12 workers are not given a payslip, both in breach of employment rights.
The impact of unpaid or delayed wages is so severe, it leads to thousands of workers having no food, said the report.
Sectors most likely to abuse workers, such as failing to pay wages, include sports activities, amusement and recreation, food and beverage services, arts and entertainment, and construction, according to the research which was funded by the Trust For London charity.
Nick Clark, from Middlesex University London, said: "It has not been easy to find accurate data on the true scale of failure to pay wages in this country and I fear that this is the tip of the iceberg in terms of painting a realistic picture of unpaid Britain.
"One of the problems is that there is no official data on non-payment. Not paying wages is a civil rather than a criminal offence which means there are no crime statistics.
"Our interim findings demonstrate that there is a desperate need for improved workers' protection and better guidance on their rights and how these can be enforced.
"With an uncertain Brexit around the corner there has never been a more important time to safeguard, protect and enhance workers' rights."