The UK’s 2015 Modern Slavery Act is ten years old on March 26. When it was passed, it was billed as “world-leading” legislation – the first of its kind to introduce a dedicated legal framework to deal with modern slavery.
But ten years on, the evidence tells a different story. The numbers of people identified as potential victims are higher than they have ever been. Yet very few people have been prosecuted. What went wrong with this “groundbreaking” law?
The Modern Slavery Act was the final piece of legislation under the 2010-15 coalition government. Championed by then home secretary Theresa May, the act was primarily about beefing up the criminal justice approach. While criminal offences like human trafficking, forced labour, slavery and servitude were previously dealt with in different pieces of legislation, the act consolidated them into one place.
The aim was to make it easier to identify and prosecute traffickers (who May referred to as “the slave-drivers”), while offering some protection to their victims.
It also included a role for the private sector through a “transparency” clause. This required bigger businesses to report what they are doing to prevent modern slavery in their supply chains. And, it created an Independent Anti-Slavery Commissioner to “encourage good practice”. Other new measures included a legal defence to victims who had been forced to commit crimes, and giving law enforcement new powers to confiscate assets from traffickers.
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However, the act did little to stop modern slavery happening in the first place. The prevention strategy mainly consisted of poster campaigns in airports and immigration processing centres.
Some argued that the act dodged the big issues around work and immigration. For example, by not addressing weaknesses in labour protections and the additional vulnerabilities migrant workers faced thanks to May’s “hostile environment” migration policies.
As prime minister, May touted the UK’s “world-leading” efforts on modern slavery to the global stage at the UN General Assembly. But a decade later, the impacts have been less than stellar.
What has been its impact?
The act has certainly raised the issue’s profile in the last ten years. Businesses now have to report on what steps they are taking to tackle modern slavery. But there are no penalties if they do not comply, and there has been limited progress on exploitation in supply chains. Recent cases involving McDonald’s and other supermarkets prove that businesses are not spotting the signs or acting effectively to prevent the issue.
The number of people identified as potential victims of modern slavery has increased significantly in the last ten years: 19,125 in 2024, nearly six times as many as in 2015. That’s at least partly because the act has improved awareness among frontline responders (organisations who refer potential victims for support).
But while more people who may have experienced modern slavery are being identified, prosecutions are very low. Only 64 adult offenders were sentenced between 2017-19 for over 22,756 potential victims of modern slavery identified over the same period. There are many reasons for this, but one is that victims may not come forward, fearing they may be detained or deported.
Immigration policies passed by the last Conservative government have also rolled back protections for modern slavery victims. In passing the Nationality and Borders Act and Illegal Migration Act, the government argued that people arriving on small boats were abusing the protections offered through the Modern Slavery Act to evade deportation. Far from world-leading, the UK became non-compliant with international anti-trafficking and human rights laws.
Many of the concerns raised during the drafting of the legislation have proven accurate. Despite repeated commitments to create a unified labour inspectorate, successive governments have dodged reform of labour market regulation.
The UK’s immigration and work visa system has also led to the potential for exploitation. Even legal migration routes and the sponsorship visa scheme have created conditions for people to be exploited. For example, in sectors such as agriculture or social care, where intermediaries sell false promises regarding employment and conditions in the UK.
Read more: How visas for social care workers may be exacerbating exploitation in the sector
Added to this, the system of support which recognised victims of modern slavery can access is creaking under pressure. It has expanded beyond what was envisaged in its original design, and there are backlogs in decision-making and questions over how appropriate it is. Thousands have declined formal identification and support because they do not feel it is worthwhile or appropriate for them.
Research has also shown that victims are not necessarily getting the support or legal defence they are entitled to. An unknown number of victims are likely to be in the UK’s prisons, where they may be subject to further exploitation.
Stopping modern slavery
The theory behind the Modern Slavery Act was that if you “get tough” on criminals and improve support for victims, you can reduce exploitation. But that hasn’t worked – modern slavery is still a huge problem in the UK.
Changing this means taking prevention seriously, and addressing the conditions and inequalities that lead to exploitation in the first place. Like other global challenges, modern slavery stems from issues like poverty, inequality and discrimination and gender-based violence.
My colleagues and I at the Modern Slavery and Human Rights Policy and Evidence Centre recently noted in our report on policy priorities that the government has an opportunity to prevent modern slavery through some of its other crime prevention efforts, as well as in forthcoming legislation such as the employment rights bill.
Without a clear and evidence-based strategy, modern slavery in the UK will persist or even grow, and the Modern Slavery Act will remain an innovative, but ultimately ineffective tool in the fight against exploitation.
Alex Balch is Professor of Politics at the University of Liverpool and is Research Director of the Modern Slavery and Human Rights Policy and Evidence Centre (PEC) based at the University of Oxford. The Modern Slavery PEC is supported by the UK's Arts and Humanities Research Council and funds research to improve understanding of modern slavery and inform better policies to address it.
