Modern Slavery Risks in the Construction Sector

This research report and summary, "Evidence Review: assessing the nature and scale of modern slavery risk in the construction sector, with focus on the housebuilding subsector" is based on research conducted by Dr Gabriela Gutierrez Huerter O, Dr Furqan Suhail, Dr Yazan Alzoubi (King’s College London). The project was co-commissioned by the Office of the Director of Labour Market Enforcement office (DLME) and the Modern Slavery and Human Rights Policy and Evidence Centre (PEC) at the University of Oxford. The research was funded by the PEC which in turn is funded and supported by the UK Arts and Humanities Research Council (AHRC). 

The Modern Slavery and Human Rights PEC and DLME have actively supported the production of research summary and the full report. However, the views expressed in this summary and the full report are those of the authors and persons interviewed or surveyed during the course of the research, and not necessarily of the PEC, DLME or Kings College London.

Background

The UK construction sector, a cornerstone of the national economy employing around 1.4 million people, reached a record value of £139 billion in 2023 due to strong growth across public and private projects. Despite this expansion, the sector is grappling with a chronic labour shortage, which has led to project delays, rising costs, and growing concern that government targets—such as building 1.5 million homes in five years—could worsen the problem. The industry's complex subcontracting chains and reliance on intermediaries have historically fostered informal and precarious work, with persistent issues around tax evasion, employment law non-compliance, and risks of labour exploitation.

These conditions have drawn increasing attention from policymakers, NGOs, and government bodies, especially in light of the Employment Rights Bill and plans for a Fair Work Agency. In response, new research has been undertaken by Kings College London to investigate the nature and extent of modern slavery in UK construction, particularly within the housebuilding sub-sector. The study aims to analyse the current evidence base, consolidate key findings, and provide recommendations for policymakers and further research.

Key Findings

1. The amount of evidence found on the nature and scale of modern slavery in the housebuilding subsector is not commensurate with the significance of this subsector in the UK economy.
2. There is limited quantitative evidence on modern slavery in construction and a particular gap in relation to evidence from those with lived experience and from commercial organisations
3. Definitional challenges resulting in inconsistent application of the rules, enforcement constraints and low prosecution rates perpetuate risks of modern slavery practice.
4. There is a spectrum of overlapping labour exploitation issues that are inconsistently documented within the construction sector. Alongside long and complex supply chains, this makes it difficult to capture a holistic view of modern slavery issues. Workers are often hidden, making exploitation harder to detect.
5. Evidence suggests that labour shortages amplify the reliance on migrant workers, including those who are either undocumented or have limited rights to work.
6. The high cost of doing business coupled with employers’ short-term profit orientation and low profit margins in the construction industry may contribute to modern slavery practices.
7. Existing evidence on modern slavery is predominantly concentrated in the south of England, particularly in London. There is a gap in research relating to risk outside of the London / South East region, in particular relating to the devolved nations.

Key Recommendations  

1. Existing data should be better utilised and effectively extrapolated to help policymakers address risks of modern slavery in construction/housebuilding. The Home Office should consider the use of specialised text analysis techniques to disaggregate NRM data by type of exploitation across different sectors, subsectors, and devolved nations. It should also provide a breakdown of instances where more than one type of exploitation occurs. Relevant Civil Society Organisations and government agencies should consider separating out data on exploitation incidents within the construction sector and should start sharing estimates and profile data on exploited workers with multiple recorded labour abuses.
2. The DLME should prioritise research that evaluates effective methods for optimising intelligence-sharing between government departments and enforcement bodies, ensuring harmonised responses that leverage all available investigative powers.
3. More research, encompassing both small qualitative research designs as well as large-scale quantitative designs are needed to generate robust primary data on the nature of modern slavery and labour exploitation in the UK housebuilding sector and the broader patterns and trends of the scale of the risk of exploitation. This research should also shift its geographical focus beyond London/South-East and to the devolved nations, where evidence is almost non-existent.
4. Future research should prioritise amplifying the voices of workers who experience and/or witness exploitation on sites and other stakeholders including frontline workers within the sector—such as labour inspectors, health and safety officers, and union representatives—who possess critical insights into exploitative practices
5. Future research should examine whether small-scale housing projects (e.g., renovations, extensions) are more or less prone to exploitation than large scale projects (e.g. large residential projects) by exploring the differences in risk factors.