Migrant leek pickers 'exploited' in the Fens
30 September 2013 Last updated at 18:26 BST
Eastern European leek pickers in the Fens are being exploited by unlicensed gangmasters, a BBC investigation has found.
Some workers claim that they have been threatened and underpaid.
Four British supermarkets where the vegetables are sold have said they will look into the findings.
Jo Taylor reports.
You can hear more on that investigation in a documentary later this evening, at 7 o'clock on BBC Radio Cambridgeshire - or on the BBC iplayer