Seven children, some as young as nine, have been found working as 'slaves' in near freezing conditions in an onion field Worcester.
The children were discovered without food or water and dressed in thin summer clothing. They were working among 50 Romanian farm labourers picking spring onions last week.
Some of the children were with their parents but others appeared to be on their own, the Gangmaster's Licensing Authority (GLA) said.
The watchdog raided the field in the Kempsey area of Worcester with police last week after a GLA enforcement officer spotted the children working 24 hours earlier as she carried out investigations at another farm nearby.
The officer, Linda Boyle, said the children, five girls and two boys aged between nine and 15, were being made to work from 7.30am until dusk.
Wellington boots that looked suitable for a five-year-old were also found in the field, suggesting even younger children had worked there.
Mrs Boyle said it was the first time children had been discovered working in fields, although rumours that the practice went on were widespread.
She said: 'I think it's absolutely appalling that the people behind putting those workers in the field have allowed these children to be taken and used as slaves picking food for our tables.
West Mercia Police have now taken six of the children into protective custody and are trying to identify their parents.
A GLA spokesman said two adults escaped from the field as the raid unfolded.
The workers said they were not sure how much they would be paid, but intelligence suggests that a household of up to 40 people would get no more than £100 a week for the job.
The GLA, West Mercia Police and the UK Border Agency are still investigating and plan to arrest at least one unlicensed gangmaster this week.
Paul Whitehouse, chairman of the GLA, said: 'In 2007 we celebrated the 200th anniversary of the end of the slave trade, but in 2010 we've got people working in appalling conditions who, while not actually being slaves, are very close to it.'
The Government currently deciding whether to sign up to the EU directive on human trafficking, which would make it easier to prosecute traffickers and protect victims.
The GLA is funded by the Department for Environment, Food and Rural Affairs.