It's billed as a kidney-shaped superfood, lauded by nutritionists. The popularity of vegan foodstuffs such as plant-based milks, nut butters and even vegan cashew cheese have contributed to a growing market for cashew nuts in the UK.

According to the Centre for the Promotion of Imports from developing countries, imports of cashews into Europe increased annually by an average rate of 17 per cent in value in the last five years. In the UK, we now consume around 19,800 tonnes a year.

But cashew shells are often processed in dire conditions, and the reddish brown cashew nut liquid within contains cardol and anacardic acid, which inflicts vicious burns and lesions on the workers who shell them by hand.

The charity Traidcraft Exchange highlighted the issue this week by blaming conditions on European supermarkets, since lowering prices force cashew companies to hire cheap labour in India and Vietnam.

Fiona Gooch, of the Traidcraft Exchange, said producers 'are under too much [price] pressure', despite agreements set by the likes of the Ethical Trading Initiative (ETI), which provides “base code” rules relating to safe and hygienic working conditions, child labour, living wages and regular employment.

To outline the process: the cashew is a rather protective little blighter (which, incidentally, are not technically a nut at all, but closer to a seed or a legume – harvested from the cashew apple, the fruit produced by cashew trees).