Modern slavery in the built environment: 5 practical lessons for businesses

On Wednesday 13 May, over 130 delegates from more than 60 organisations came together in Birmingham for ‘Modern Slavery in the Built Environment: Keeping Pace, Taking Action’. The conference was hosted by Supply Chain Sustainability School in partnership with CCLA Investment Management.

Across the day, 18 expert speakers explored the changing legal, investor, and client expectations across the built environment. Here are five key insights and practical takeaways for businesses.

1. Modern slavery is prevalent in the built environment

The built environment is a high-risk sector for modern slavery and labour exploitation because of high labour demand, skills shortages, long and complex supply chains, and the widespread use of subcontracted, migrant and self-employed labour.

An estimated 2.6 million people in the construction industry are in forced labour, accounting for 16% of adults in forced labour worldwide. Data from Unseen’s Modern Slavery & Exploitation Helpline also points to a growing risk in the UK. In 2025, the Helpline recorded 710 potential victims across 150 construction-related modern slavery cases, a 44% increase in potential victim numbers compared with 2024.

In her address, Dame Sara Thornton, Consultant in Modern Slavery at CCLA Investment Management, warned that despite the scale of the risk, the sector’s response remains underdeveloped. The same characteristics that increase the risk of exploitation also make it harder to identify and address.

Key takeaway: Businesses must start from believing that modern slavery is in their direct operations and supply chains and act accordingly; the chances are it is. In fact, claiming “zero-tolerance of modern slavery” can suggest that a business has not fully understood the risk or its prevalence and so this claim should be avoided.

2. Businesses can no longer ignore modern slavery due diligence

Expectations on modern slavery due diligence are evolving. Where a suspected case arises, businesses are increasingly being asked not, what did you do wrong, but what did you do right: Did the business know, or should it have known, about the risk? What steps did it take to identify, mitigate and prevent harm? And were those steps meaningful and proportionate?

Emily Pica, Of Counsel at Omnia Strategy, illustrated this through the recent Dyson case. Migrant workers from Nepal and Bangladesh brought claims against Dyson in the UK over alleged forced labour at a Malaysian factory operated by a tier 1 supplier. The workers argued that Dyson knew, or should have known, about the risks and failed to take sufficient action to mitigate it. Dyson denied the allegations, and the case was later settled without admission of liability, however this landmark case showed that UK courts may be willing to hold businesses accountable for serious labour abuses in overseas supply chains. Separate proceedings involving Lafarge and Vinci in France point to the same broader shift towards increased legal scrutiny of businesses over overseas supply chain harms.

Key takeaway: Businesses must demonstrate what actions they have taken to find, fix, and prevent modern slavery in their direct operations and supply chain and how these are proportionate to the risk. Due diligence can no longer be treated as a compliance burden but as a core business process that provides a critical line of defence when a suspected case arises.

3. Businesses must look for the right things in the right places

Effective modern slavery due diligence must focus on harm to people, not only risk to the business. These risks are not separate; where workers are vulnerable to exploitation, businesses are also exposed to legal, operational, financial and reputational consequences. Professor Jo Meehan, Director of Centre for Sustainable Business at University of Liverpool Management School, challenged businesses to think differently about what they are looking for and where they are looking. As she put it, “Exploitation persists not because we cannot see it, but because of how we consider risk, harm and responsibility”. For example, greater supply chain visibility does not always mean better understanding; if supplier audits are designed to prove that nothing is wrong (reinforced by corporate claims of “zero-tolerance”), this skews what businesses look for and how they interpret the results. This can create defensive reassurance rather than uncover exploitation.

Looking in the right places also means examining the everyday business decisions that may create or exacerbate modern slavery risk. Pressure on suppliers and subcontractors to deliver work faster and at lower cost, particularly amid skills shortages and supply chain disruptions, can cause due diligence and responsible sourcing to be sidelined. Decisions are made in the name of urgency, while the potential for harm to workers is pushed out of view.

Key takeaway: Approaches to due diligence must start with preventing harm to people. As part of this, businesses must hold up a mirror to their own commercial practices, looking inward to understand how their pricing, lead times, procurement decisions and supplier requirements may obscure or increase modern slavery risk. Ultimately, a people-centred approach also helps businesses better understand their own exposure, because risks to people and risks to business are closely intertwined.

4. Finding modern slavery is a sign of effective due diligence

In the same way greater visibility does not automatically equal better understanding, a business reporting no cases of modern slavery is not necessarily a sign of good due diligence. Consistently finding nothing may indicate gaps in where and how a business is looking. It may mean that workers do not trust the whistleblowing routes available to speak up, or that checks are focused on strategic suppliers and tier-one relationships while harm sits in informal work, lower tiers or subcontracted arrangements. By contrast, identifying exploitation in a high-risk sector can demonstrate that a business’s risk assessment and due diligence processes are working. This principle is reflected in the UK government’s Transparency in Supply Chains (TISC) guidance as well as in the CCLA’s Modern Slavery Benchmark 2026. More than half of the benchmark’s available points fall under “Find it”, and businesses cannot score under certain questions unless a case of labour exploitation or modern slavery has been identified. This weighting recognises that uncovering exploitation is often the hardest, but most important, part of due diligence.

If a suspected case of modern slavery or labour exploitation is identified, businesses must also be transparent. Disclosure raises awareness of exploitation risks within a business’s own supply chain and across the wider industry. It also supports accountability and allows others to learn from real cases. First Solar provides a strong example. After a third-party audit identified forced labour in its supply chain, the company reported the case in its annual sustainability report and proactively shared its findings with The New York Times. Forced-labour expert Dr Laura Murphy later praised its response as an example of meaningful transparency.

The conference showed that this move towards modern slavery transparency is taking place across the wider sector. During the industry panel, a representative from a tier 1 contractor asked, “Who here has found a case of modern slavery?”. They raised their own hand, and others gradually followed. By the end, representatives from around ten organisations had done the same.

Key takeaway: Businesses should be open about the cases it identifies, how it responds, and what changes it makes as a result. Finding modern slavery can show that due diligence is working. Failing to look properly, or sweeping identified cases under the rug, allows exploitation to remain hidden.

5. Collaboration and progress over perfection

Modern slavery is systemic and persistent. No organisation can solve it alone, and smaller businesses in particular may struggle to map and influence complex lower-tier supply chains by themselves. Many businesses share suppliers, labour models and supply-chain risks. Collaboration allows them to share intelligence, combine their leverage and develop practical responses to common problems. The conference demonstrated the value of sector-wide collaboration by bringing together leading voices from industry, investment, policy, academia and survivor advocacy. These discussions can help organisations strengthen the internal conversation and move modern slavery higher up the business agenda. Collaboration with people who have lived experience of modern slavery is particularly important. In his session, Amar Lal, Child and Human Rights Activist and Survivor Leader, reinforced that survivor engagement is not a symbolic exercise. It provides valuable expertise that can help businesses understand how exploitation occurs and design more effective responses.

The scale of the challenge should not become an excuse for inaction. During the panel discussion, Sally Taylor, Sustainable Procurement Specialist at Defra, and Lucy Shearer, Head of Ethical Supply Chains at Great British Energy, stressed that businesses do not need complete supply chain visibility or guarantees that modern slavery is absent before they act – neither is a realistic expectation. A strong business speaks honestly about its risks and takes practical, proactive and proportionate steps to prevent harm to workers.

Key takeaway: Businesses need to make a start, prioritising progress over perfection. Begin by identifying where the greatest risks to workers lie, considering the severity of potential harm, how many people may be affected, and how difficult that harm would be to remedy. Develop practical measures to prevent and mitigate these risks. Work with suppliers to improve practices and build capacity rather than simply passing responsibility down the supply chain. Draw on the expertise of workers and people with lived experience, alongside suppliers, clients, investors, NGOs and academics.