London: Britain’s anti-slavery chief Kevin Hyland is preparing to step down after almost four years in the role, which saw the country enact a landmark law and spearhead the global drive to adopt and meet a United Nations goal of ending modern slavery by 2030.

Hyland, appointed independent commissioner in 2014 as part of Britain’s widely lauded Modern Slavery Act, told journalists he would leave the post by August to head up a children’s charity in Ireland.

He said the world-leading law had been a “game-changer in many ways”, but acknowledged criticism from anti-trafficking campaigners about a lack of convictions, mixed support for victims, and limited action from businesses to address slavery.

The law introduced life sentences for traffickers, measures to protect people at risk of being enslaved, and made large companies scrutinise their supply chains for forced labour.

Law enforcement agencies need to ensure tackling slavery is a priority, and pursue more prosecutions, while firms who flout the law by failing to disclose what action they have taken to clean up their supply chains should be penalised, Hyland said.

“The legislation is not yet being fully utilised or enforced ... but it is still in its infancy,” said Hyland, who was appointed by British Prime Minister Theresa May in her previous role as Home Secretary where she championed the law.

Yet Britain has set an example for other nations to follow — Australia is expected to pass a similar law this year — and was instrumental in securing a UN target to end slavery as part of 17 global development goals adopted in 2015, Hyland said.

“That was a major achievement on the global stage,” he said, adding that Britain’s leadership has enabled the country to work with others, from Nigeria to Vietnam, to fight a $150-billion-a-year-trade (Dh550 billion) estimated to enslave 40 million people worldwide.

Hyland said he had been frustrated by the government interfering with a role intended to be separate from the state, although he declined to elaborate, and urged autonomy for his successor — a call echoed by leading anti-slavery activists.

“Tackling slavery at home gives Britain the authority to talk to other countries about their efforts to address the issue,” said Nick Grono, chief executive of the Freedom Fund, the first private donor fund dedicated to ending slavery.

“But to do that effectively, the next commissioner needs to be able to assert their independence in the role.” The government was not immediately available to comment.

At least 13,000 people across Britain are estimated by the government to be trapped in forced labour, sex exploitation and domestic servitude — but police say the true figure could be in the tens of thousands with anti-slavery investigations rising.