Thousands of children are working as slave labour on West African cocoa farms to help produce Easter chocolate for the UK, campaigners have warned.
Manufacturers describe child slave labour as "unacceptable"
The International Labour Organisation says 12,000 children have been trafficked to the Ivory Coast.
A coalition of anti-slavery charities says they work long hours for no pay and little food on the plantations.
British chocolate manufacturers said a certification scheme was being set up to tackle "unacceptable" conditions.
'Background of poverty'
The coalition, called Stop the Traffik, wants the manufacturers to declare chocolate "traffik-free" so consumers can be sure they are not supporting child slave labour.
Stop the Traffik's chairman Steve Chalke said: "These youngsters come from a background of poverty, and are even knowingly sold by their parents sometimes.
"Often what will happen is the parents are starving, they're poor, they have nothing and somebody comes along and says 'I'll take your son, he'll work on my farm and I'll give you some money'.
"They think 'We'll get money so we can eat and our son gets a job'. They don't know what he's going to is a living hell."
The call for a "traffik-free guarantee" has been backed by MP Mike Hancock who has tabled an Early Day Motion in the Commons signed by more than 50 fellow MPs.
Charity Save the Children says many children in West Africa also work in hazardous conditions on family farms.
The Biscuit, Cake, Chocolate and Confectionery Association (BCCCA) said human trafficking was unacceptable.
Alison Ward, of the BCCCA, said UK manufacturers were spending about £8m a year to develop certification and monitoring schemes.
"We all want to ensure that the cocoa we buy is grown using internationally approved labour standards - notably without the worst forms of child or forced labour," the association said.