Prime Minister Theresa May is to announce plans to create a new transparency registry to alert consumers to companies that exploit forced labour.

Mrs May is expected to reveal a set of proposed measures that would build on the UK’s modern slavery laws on Tuesday.

The PM, who stepped down as leader of the governing Conservative Party earlier this month, is also due to call on world leaders to face up to their “moral duty” and take action to halt modern slavery.

Speaking at the United Nations’ International Labour Organisation centenary conference in Geneva, Mrs May will urge business and political representatives to do more to protect the millions of people being held and forced to work against their will.

She is expected to say: “No leader worthy of the name can look the other way while men, women and children are held against their will, forced to work for a pittance or no pay at all, routinely beaten, raped and tortured.

“So, those of us who can speak out, who have a platform from which to be heard, have a duty, a moral duty, to raise our voices on their behalf.”

As then home secretary, Mrs May oversaw the introduction of the UK’s Modern Slavery Act in 2015, said to be the the first of its kind in Europe.

The outgoing Prime Minister now plans to announce further measures to help tackle modern slavery at home and overseas.

These include funding a £10 million programme to reduce the exploitation of children in Africa’s agricultural industries and the creation of a new international modern slavery and migration envoy to help co-ordinate the UK’s work with other nations.

Under the Modern Slavery Act, large businesses have a duty to be open about their efforts to cut out abuse from their supply chains.

Mrs May now wants to create a new central registry of modern slavery transparency statements to give consumers the ability to make informed choices about businesses.

She will also urge the Government to find ways to make it harder for companies to avoid scrutiny and expand transparency laws to cover the public sector.

“Modern slavery reaches into every corner of our lives – in the clothes we wear, the food we eat, the services we pay for,” Mrs May will say.

“Yet for many years it seldom captured the world’s attention or outrage – allowing those who trade in human misery to quietly continue their work and allowing all of us to look the other way as we benefited from the forced labour of this growing underclass.

“Throughout my time in government – first as my country’s home secretary, more recently as its Prime Minister – I have fought to change that.”

Mrs May will argue it is “more important than ever” to “accelerate” the fight against modern slavery and “do all that we can to meet the UN’s goal of ending this abhorrent crime by 2030”.