Chocolate means different things to different children. For kids in rich countries, it is a brightly packaged, delicious treat. For those in poor countries — especially in west Africa — it is all too often a burden: a $100bn product whose key ingredient, the cocoa bean, they must work hard to cultivate.

Child labour has long been a feature of cocoa production in Ghana and Ivory Coast, which together account for about 60 per cent of the global supply. That has led to fierce criticism of the multinational food businesses that buy the cocoa.

Last year, a lawsuit filed by campaign group International Rights Advocates against Swiss conglomerate Nestlé and agriculture trader Cargill, accusing them of being complicit in the use of forced child labour, made it all the way to the US Supreme Court, before being thrown out.