Seven Romanian children between the ages of nine and 16 have been found working in a field in Worcestershire.
The Gangmasters Licensing Authority (GLA) and West Mercia Police found the children with a group of adults in the field in the Malvern Hills district on Wednesday.
The children, some of whom were with their parents, were taken into police protection.
A GLA spokesman said no arrests had been made but inquiries were ongoing.
The spokesman said officers found a group of 50 Romanians working where no licensed gangmaster could be established.
There was also a small group of Indian workers who were working for a licensed gangmaster.
The children had been found picking spring onions.
The spokesman said none of the workers, including the children, were adequately dressed for the cold conditions.
Linda Boyle, of the GLA, said it was the first time the authority had found children working in fields anywhere across the UK, though she had heard rumours that it was happening
She said two men escaped as attempts were made to detain them.
She said: "I wasn't shocked we found children because I had heard rumours. Last year, I found a baby's glove in a field.
"I was shocked we found so many.
"You have to be appalled."
Six children remain in care, she said, and social services were trying to identify them and their parents.