Car wash workers are being forced to "live in squalor", Wakefield Council's deputy leader has said, after three men were found to be earning a measly £3.85 per hour.
Denise Jeffery said officers were finding numerous cases of migrant workers living in "appalling conditions" in rented accommodation, while being employed at car washes on criminally low pay.
Coun Jeffery's comments follow the discovery of a trio of foreign workers at a house in Wakefield.
Enquiries led enforcement teams to a car wash in Barnsley, where the men were employed, but paid less than half the minimum wage for those aged 25 and over.
In a report for next week's full council meeting, Coun Jeffery said that the three workers had been found living in "rented squalor".
She added: "Their landlord had failed to carry out even the most minor repairs and was charging the tenants almost all their earnings in rent for the property.
"The three men were picked up every morning and taken to a car wash in Barnsley to work about 13 hours a day for £50.
"They have confirmed that they have not been trafficked and are working at their own volition.
"This is sadly not an uncommon occurrence and the same story is heard at nearly every car wash we visit where living conditions are generally appalling."
Last November, a committee of MPs chaired by Wakefield's Mary Creagh recommended that hand car washes be licensed in a bid to "prevent modern slavery in plain sight".
More than a quarter of cases filed by the Modern Slavery helpline concern car wash workers, but the BBC reported that there were only minimum wage 14 prosecutions in the sector between 1999 and 2018.
Back then, Ms Creagh said: "Hand car washes are a common sight in our towns and cities.
"Yet they hide the widespread exploitation of workers through illegally low pay, poor working conditions and, in some cases, forced labour."
Local Democracy Reporting Service