The International Labour Organisation on Tuesday launched a campaign aimed at mobilising people around the world to lobby their governments to end modern-day slavery.

The 50 for Freedom campaign, organised in partnership with the International Organisation of Employers and the International Trade Union Confederation, is calling on governments to ratify the forced labour protocol.

The campaign is called 50 for Freedom because it hopes to persuade at least 50 countries to sign up to the protocol, which is an attempt to bring legislation on forced labour and trafficking up to date. The previous convention dates from 1930.

The new text was agreed by a majority of ILO member states in 2014, and includes measures to prevent contemporary forms of slavery as well as protecting and compensating victims. It can only come into force when at least two countries have ratified it. So far, Niger is the only country to have done so.

Trafficking experts believe a new set of legal tools is urgently needed to tackle the more complex forms of modern slavery.

Houtan Homayounpour, senior programme and operations officer for the ILO’s special action programme against forced labour, said: “The original ILO convention was one of the oldest ILO conventions, although one of the most ratified. So states thought there were gaps [in protection] … they wanted a new treaty.”

One new obligation for states is to ensure that people who are trafficked are not prosecuted for crimes they commit while under the control of traffickers.

In the UK, campaigners say many trafficked Vietnamese children are sent to prison for drug-related offences.

Another new and – campaigners say – important addition to the legislation is compensation for victims, many of whom will be in a country illegally. Homayounpour said there was a big gap in protection for people who will be subject to immediate deportation. “Very often these workers find themselves without access to any help; they are kicked out of the country or imprisoned and the research shows they are then more likely to fall victim to traffickers again. This is a real weakness – it happens all over the world.”

He acknowledged there will be a lot of work to do in the next two years to get countries to ratify the protocol. “Niger is showing leadership in wanting to be the first to ratify this – it’s fantastic from a continent that has historical ties to slavery that they no longer want to be a part of this. Definitely, it will require more work in certain countries because of the lack of structure, the weak labour inspection services [and] financial limitations.”

There are an estimated 21 million forced labour victims worldwide. Forced labour in the global private economy generates illegal profits of $150bn (£89bn) a year according to ILO research last year. That is as much as the combined profits of the four most profitable companies in the world.

The Ethical Trading Initiative, which brings together companies, NGOs and trade unions to promote workers rights, has produced research with the Hult International Business School to coincide with the launch of the campaign, showing that many large companies operating in the UK believe there is a likelihood of modern slavery occurring at some point in their supply chain.

Out of 21 companies across a range of businesses, from clothing to food, two-thirds acknowledged the risk of forced labour in their supply chain, although even those who want to tackle the problem are worried about the risk to their reputation if they are open about that concern.

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Cindy Berman, head of knowledge and learning at the ETI, said it was vital companies had a safe space where they could discuss the challenges posed by modern-day slavery. “Companies are willing to be more open and honest that slavery exists in their supply chain. We were heartened to find that companies know they need to work with suppliers, that they cannot appoint auditors to do their due diligence for them. Audits have failed to pick up the worst forms of exploitation and abuse because it is so well hidden. They are beginning to see they need a new due diligence.”

Despite the positive changes in attitude within the industry, the protocol was needed more than ever, she said. “We are seeing a sort of parallel process. Some countries are recognising they need better laws and policies but alongside that the nature of the labour market is increasingly deregulated, so the protection is not there for vulnerable workers. I think there is now a recognition, the ILO forced labour protocol is a really good place for countries and the private sector to engage on this issue. It’s now on the table in a way it never was, but we should not be complacent – we have to keep the pressure up.”

Homayounpour believed the involvement of people around the world would eventually make the 50 for Freedom campaign successful. “Citizen support is fundamental,” he said. “It will get the general public to create a movement from the ground. I am an optimist. Through history there have been things that people thought could not be eliminated but they were proved wrong – and forced labour will be one of those examples.”

