How is the UK Construction Industry Impacted by Modern Slavery?

Modern forms of slavery continue to present a real and ongoing risk in the UK construction sector.  Exploitation of labour is sadly more commonplace than previously thought – in housebuilding in particular - often occurring close to site and hidden in complex supply chains and labour only arrangements. Although modern slavery is under researched and poorly understood, recent reporting on housebuilding has underscored familiar risk factors: high reliance on temporary and migrant labour, multiple and sometimes opaque layers of subcontracting, price pressures, late changes to programmes, and weaker visibility below Tier 1 contractors. For construction industry professionals, the agenda is shifting from policy statements to demonstrable, risk based due diligence across supply chains underpinned by credible data.

What are the Impacts of Modern Regulation?

The Modern Slavery Act 2015

In accordance with the Modern Slavery Act 2015 (MSA), commercial organisations in the UK with global turnover of £36 million or more must publish an annual modern slavery statement, approved by the board and signed by a director, setting out steps taken to ensure slavery and human trafficking is not taking place in their operations and supply chains (or that no such steps were taken). In line with recent statutory guidance on transparency in supply chains (TISC Guidance), which significantly raises the bar on what’s expected to be disclosed in a modern slavery statement, statements are expected to include information about organisational structure, policies, due diligence processes, risk assessment and management, effectiveness metrics and training. We have written on the MSA and the TISC Guidance in more depth in two previous articles here and here. 

The Procurement Act 2023

Public procurement has also seen regulations tighten under the Procurement Act 2023: contracting authorities now have enhanced powers to exclude suppliers for modern slavery offences and to consider ethical supply chain risk in award and contract management. For developers, contractors and suppliers, the effects are real: any persons bidding for public contracts must require stringent due diligence, audit, and reporting requirements across their supply chain. Where a supplier or “connected person” has been found guilty of slavery or human trafficking under the MSA, that contractor is automatically excluded from the tender process.

Procurement Policy Note 009 

The Procurement Policy Note 009 (PPN) is updated in line with the Procurement Act 2023 and Procurement Regulations 2024. Organisations should designate procurements as low, medium or high risk, on the basis of six core characteristics (industry, nature of workforce, geographic location, operating context, commodity type, and business/supply chain model). For high-risk procurements, suppliers should be contractually obliged to implement anti-slavery policies, notify authorities of relevant incidents and permit audits and inspections. The PPN also underscores the importance of acting proportionally and prioritise victim welfare, requiring organisations to consider the impact on SMEs and other smaller or voluntary organisations. 

TISC Guidance

In addition to setting expectations for organisations’ modern slavery statements, the TISC Guidance offers guidance on how to identify risks in supply chains. It recommends assessing risk across six main areas: industry type, nature of workforce, supplier location, operating context, commodity risk, and business model. Adopting this approach in the private sector enables more effective triage and target setting – facilitating salient risks to be disclosed and acted upon. The TISC Guidance goes on to recommend investing in AI and machine learning to detect irregularities, from payment patterns to labour practices.

What Should Construction Industry Professionals Focus On?

The most effective approach is tightly focused on the highest risk areas. For developers, that typically means strengthened oversight of principal contractors’ labour sourcing, more rigorous pre qualification on labour standards, and contractual rights to information and investigation at lower tiers (i.e. sub-contractors and suppliers). For contractors, attention should centre on labour only subcontractors, agency labour, and trades with high churn or cross border recruitment.

The following are actionable steps to mitigate modern slavery risk:

• Conduct risk assessments to map exposure across the six main areas identified in the TISC Guidance. The findings of this assessment should be documented and incorporated into your risk register and statement.
• Embed responsible recruitment across the supply chain: this entails prohibiting the payment of excessive and/or predatory fees to secure employment across all sites, auditing labour providers to check for evidence of irregularities in employment practices (i.e. withholding documents, debt bondage etc), and incorporating such safeguards during the contracting and onboarding process.
• Utilise contractual levers: include contractual requirements to disclose relevant information, conduct site checks and worker interviews, and maintain control over the identity of subcontractors by limiting further subcontracting wherever possible.
• Address factors that drive risk: short, unrealistic lead times, last minute changes to the programme, and artificially low pricing, all of which flow pressure down the supply chain, incentivising unscrupulous and sometimes illegal practices.
• Effective governance policies and training: ensuring senior level oversight of and responsibility for modern slavery risk, as well as equipping employees across your business to be able to identify modern slavery, is a cornerstone of ensuring effective, transparent and timely mitigation of such risks. 

What to Expect in the Future?

Although the TISC Guidance does not change the legal requirements of the MSA, it has been viewed by many as an attempt to bring company behaviour more in line with international standards and best practice, as well as a stepping stone toward a future amended, more robust Modern Slavery Act.

To that end, in December 2025 the UK Independent Anti-Slavery Commissioner released model legislation for a new law in the UK to protect human rights, including by introducing mandatory human rights due diligence. This is against the backdrop of the UK Government having previously launched a review of its approach to responsible business conduct, focusing on the global supply chains of businesses operating in the UK. Among others, the proposed law would:

• have a “failure to prevent” model seen in other UK legislation whereby when a serious human rights harm occurs, and a company is involved in the harm, it would be responsible for the harm unless it can prove it conducted reasonable due diligence;
• provide for a general ban on exporting, importing or making available on the UK market products made with, or transported with, forced labour;
• require companies to publish an annual human rights statement, replacing the existing MSA requirement. In the coming months, we expect to see continued discussions on the possibility of imposing mandatory human rights due diligence in the UK.

Key Takeaways

Modern slavery in UK construction thrives in the pressure points of the sector: 

• heavy reliance on temporary and migrant labour,
• opaque multi-tier subcontracting,
• programme volatility, and
• aggressive pricing. 

The regulatory direction of travel is clear: board-level accountability under the MSA and tougher exclusion risks in public tenders under the Procurement Act 2023 demand a shift from words to action.

In light of the TISC Guidance and indications of moving toward new legislation, there will be good reason for companies to update their modern slavery statements. Key stakeholders, including investors, lenders and corporate customers, are likely to look for increased disclosures which give more detail into the actions a company is taking in the fight against modern slavery in its business and supply chains rather than a tick box. Any company with a valuable brand or that makes claims to strong ESG credentials should pay particular attention.

The practical response is equally clear: developers and contractors should adopt the TISC Guidance six-factor risk assessment; embed responsible recruitment and worker safeguards into contracts and onboarding; avoid rewarding unsustainably low-cost models; and support this with training, data, and transparent reporting. Done well, this is not only the right outcome for workers, it also strengthens business resilience, protects eligibility for major work, reduces reputational and criminal risk, and builds the investor and customer trust on which the sector relies.