Are construction companies taking modern slavery seriously?

The UK construction industry acknowledges the critical importance of tackling modern slavery, but recent data highlights a significant gap between having Modern Slavery policies in place and taking real, measurable action. To address this issue effectively, companies must go beyond box-ticking exercises to embrace due diligence and improve transparency across their supply chains. 

This blog aims to clarify why awareness of modern slavery in construction is crucial, the difference between awareness and action, recognising the signs of modern slavery, the effects of the Procurement Act, plus ways to demonstrate appropriate awareness and Modern Slavery Act compliance within the industry, with Constructionline.

 

The gap between modern slavery policies and action in construction 

Research from Unseen UK¹ reveals that, in 2024, the construction industry ranked second only to the care sector for labour exploitation cases (105 reported) and potential victims (492 identified). Further findings from King’s College London Business School² reveal ‘overlapping forms of labour exploitation… from unpaid wages and health and safety breaches to more severe practices such as debt bondage and forced labour.’ 

Whilst many are aware of having a Modern Slavery statement, it differs when it comes to working on projects, including informal hiring practices. Fortunately, by requesting subcontractors meet a minimum certification threshold, main contractors can be assured they’ve done their due diligence on their supply chain members and demonstrate the standards they require, including the Common Assessment Standard.

 

Why supply chain transparency is essential

Supply chain transparency is the first line of defence against modern slavery in the construction sector. With complex, multi-tiered supply chains and a heavy reliance on agency labour, the risk of exploitation significantly increases further down the chain. 

Transparency enables main contractors to: 

• Mitigate risk: Identify vulnerabilities beyond Tier 1, including Tier 2 and Tier 3 suppliers, where oversight is typically limited. 
• Protect brand reputation: Avoid the severe reputational damage associated with human rights abuses. 
• Ensure compliance: Meet the stringent requirements of the Modern Slavery Act 2015 and the Building Safety Act. 

 

Recognising the signs of modern slavery in construction

To combat exploitation effectively, site managers and workforce personnel need training to spot the signs of forced labour. Common indicators include: 

• Restricted freedom: Workers appear to be controlled by others and are rarely left alone. 
• Appearance: Individuals may lack personal belongings, wear the same clothing repeatedly, or not have the proper PPE. 
• Behaviour: Reluctance to speak with others, appearing frightened or withdrawn, or showing signs of physical abuse. 
• Financial control: Workers do not have access to their earnings or hold their own identification documents.

 

Updates to the Modern Slavery Act and the Procurement Act

The regulatory landscape is evolving. The latest government guidance (updated for 2025) and the Procurement Act 2023 have introduced stricter expectations for businesses. 

It is now more important than ever for main contractors to work with subcontractors who actively implement measures to prevent modern slavery. Under the Procurement Act 2023, public contracting authorities have stronger powers to exclude suppliers with evidence of modern slavery within their supply chains. This makes a proactive approach not only ethical but essential for securing future tenders. The updated 2025 government guidance further emphasises the need for ongoing improvement, urging all levels of the supply chain to review, enhance, and report on their anti-slavery measures regularly.

1. Striving for improvement

The government’s updated guidance promotes a culture of continuous improvement. Filing a static statement is no longer sufficient – companies must demonstrate measurable progress in their anti-slavery efforts each year. 

2. Enhanced due diligence

Under the Procurement Act 2023, contracting authorities have greater powers to exclude suppliers from public sector tenders if there is credible evidence of modern slavery in their supply chains. Robust due diligence is now a commercial necessity for winning public sector contracts.

3. Focus on recruitment fees

There is renewed emphasis on the ‘Employer Pays Principle‘ (covered in PPN 02/23), ensuring workers are not charged fees for their employment – a common practice that often leads to debt bondage.

 

How Constructionline helps main contractors achieve transparency 

Managing compliance across a fragmented supply chain can be challenging.  

At Constructionline, we help simplify the process by offering a centralised platform for construction supply chain management: 

• Verified network: Access a network of 30,000+ verified subcontractors, ensuring your supply chain meets high verification standards. 
• Get your supply chain aligned with the Common Assessment Standard: 80% of UK suppliers achieve their Common Assessment Standard certification through us! This industry-standard assessment includes rigorous questions on modern slavery policies and prevention, reducing the administrative burden on your procurement team. 
• Risk management: Use Risk Radar to filter and select suppliers based on their verified compliance, significantly reducing risk. 

Supporting subcontractors to demonstrate compliance 

For subcontractors – who make up 9% of the UK’s GDP – navigating the Modern Slavery Act can feel overwhelming. Constructionline provides support by: 

• Streamlined onboarding: Fill in our question sets once and pre-qualify for more opportunities, faster. 
• Guidance and Resources: Offering clear advice to help achieve compliance with the Modern Slavery Act, regardless of company turnover. 
• Visibility: Enabling compliant subcontractors to showcase their ethical practices to top-tier main contractors, unlocking new commercial opportunities. 

 

Frequently Asked Questions 

Does the Modern Slavery Act apply to construction SMEs?
Legally, the reporting requirement (Section 54) only applies to organisations with an annual turnover of £36m or more. However, SMEs are increasingly required to demonstrate compliance to secure contracts with larger main contractors, who must audit their supply chains. 

What are the penalties for non-compliance with the Modern Slavery Act?
While there are currently no criminal penalties for failing to produce a statement, the Procurement Act 2023 allows for the exclusion of non-compliant suppliers from public tenders, and the reputational damage can be significant. 

How often should modern slavery statements be updated?
Statements must be published for each financial year. Best practice suggests publishing them within six months of the financial year-end, showing clear progress from the previous year.