Britain’s top companies will be tasked with hiring more boardroom directors from black, Asian and minority ethnic backgrounds under plans being drawn up by the Liberal Democrats leadership candidate Layla Moran. Announcing the policy in the wake of the Black Lives Matter protests around the world, the favourite to replace Jo Swinson as Lib Dem leader said companies listed in the FTSE 350 should each have at least 15% of board directors from a BAME background. The target, which would be voluntary, would mean each firm having at least one BAME boardroom director on average. Moran said she wanted business to take the lead on the target, which should be met within five years, but that failure to make progress would require government intervention. Speaking in an interview with the Guardian to unveil the policy move, Moran said businesses needed to make their efforts to promote BAME representation at the top of the corporate ladder a priority. “I hear over again from activists and those making the case for this that it’s all words and no actions. It’s no longer good enough to pay lip service to these inequalities; we have to do something about it. “Many companies have been trying. However, I think it hasn’t been made a high-enough priority by a lot of them. Black Lives Matter has really highlighted the fact there is more that could be done,” she said. Moran is the bookies’ favourite to beat Ed Davey, the Lib Dems’ interim leader, to take charge of the party. The result of the leadership contest will be announced on 26 August. More than a third of Britain’s biggest companies are on track to miss a government-backed target to have at least one director from an ethnic minority by 2021. According to an update published in February by the Parker review, 37% of firms in the FTSE 100 had no non-white board directors. The figure rises to 69% of companies in the second-tier FTSE 250 index. Limited progress has been made since 2017, when Sir John Parker, a former chairman of the mining firm Anglo American, led a review into boardroom diversity for the government. At the time, 51 firms in the FTSE 100 had no directors from BAME backgrounds, which led him to put forward the voluntary “one by 21” target. Despite the likely failure of many of Britain’s biggest firms to hit the target, Moran said she believed a voluntary, industry-led approach was still the best way to boost boardroom diversity. The Oxford West and Abingdon MP said she wanted to replicate the progress in increasing gender diversity in the boardroom led by Dame Helena Morrissey and the 30% Club, a group of senior City executives seeking to promote women on company boards. Women now hold a third of board positions in the FTSE 100, almost a year sooner than expected. Some countries have imposed boardroom gender quotas, including France and Norway, and have higher proportions of women on boards. Saying that the Lib Dems were the natural party of business and that she favoured a liberal approach rather than legislation, Moran said companies would respond to a tougher target. “A target like this would increase the amount of scrutiny and transparency the business sector would be putting on itself. It would be a real message of positive change in the current climate of Black Lives Matter, where people really want to see action,” she said.