British companies' efforts to tackle modern slavery remain "wholly inadequate" three years after the country introduced some of the world's toughest legislation on the issue, a study published on Monday found. Britain's 2015 Modern Slavery Act requires businesses whose turnover exceeds 36 million pounds ($48 million) to produce an annual statement outlining actions they have taken to combat slavery in their supply chains. The study by the Business and Human Rights Resource Centre (BHRRC), a monitoring group, found that while most of the FTSE 100 largest companies listed on the London Stock Exchange complied, their statements were vague and lacked detail.