In the large, sparsely populated desert country of Mauritania, slavery is rife – despite being outlawed in 1981 and made a crime against humanity in 2012.

Mauritania, on the western coast of the Sahara, has the highest prevalence of slavery per head of population, according to the 2013 Global Slavery Index. Compiled by the anti-slavery charity Walk Free Foundation, the index found that 151,000 people – almost four per cent of the entire population – may be living in slavery.Estimates by other groups put this figure at up to 20 per cent.