Modern slavery refers to situations where individuals are controlled, exploited and unable to leave due to threats, debt or coercion. In construction, this often appears through hidden recruitment practices, informal labour supply chains and poor oversight of subcontracted teams.

This article explains how modern slavery can affect construction projects and steps to take to minimise the risk.

Why Construction Faces Higher Modern Slavery Risks

Construction is recognised as a high-risk sector because it relies on temporary labour, complex subcontracting structures and materials sourced from global supply chains with limited transparency.

Subcontracting Layers

Long chains of subcontractors make it difficult to see who supplies labour, where workers come from and whether control or coercion is present.

Temporary and Agency Workers

Fast-paced hiring and reliance on labour agencies increase the risk of poor checks, weak documentation and inconsistent supervision.

High-Risk Materials and Products

Materials such as stone, steel or bricks may originate from regions known for forced labour. Contractors often overlook the upstream stages where exploitation occurs.

Legal Duties for Contractors in the UK

Contractors must comply with legal requirements that focus on transparency, safe employment and verification of worker status. These duties help reduce the risk of exploitation across construction sites. They include:

  • Modern Slavery Act Duties: Organisations covered by the Modern Slavery Act must publish a transparent statement, carry out due diligence and show the steps taken to identify and reduce modern slavery risk.
  • Health and Safety at Work Duties: Worker protection includes ensuring workers are not forced to operate in unsafe or coercive conditions. Awareness of exploitation forms part of responsible site management.
  • Right-to-Work Checks: Contractors must confirm a worker’s right to work in the UK. Proper checks prevent the recruitment of individuals controlled by traffickers who hold their documents.

Warning Signs of Modern Slavery on Site

Warning signs help supervisors recognise when a worker may be under control or facing coercive conditions. These signs often appear through behaviour, appearance or living arrangements.

Worker Behaviour and Movement

Workers who seem fearful, avoid contact or appear supervised by someone not linked to site management may be under control. Restricted movement or reluctance to speak freely is a key warning sign.

Pay and Document Issues

Workers who do not hold their own passports, lack control of bank accounts or report unpaid wages may be experiencing exploitation.

Poor Living or Transport Conditions

Cramped shared housing, controlled accommodation or unsafe transport arranged by third parties may signal a wider pattern of coercion.

Modern slavery training details how modern slavery happens in the UK and what to do if you suspect it.

How Contractors Can Prevent and Respond

Contractors must use clear systems to prevent exploitation and show strong oversight of labour arrangements. Effective procurement, supervision and reporting improve worker protection and support compliance. 

Strong Procurement and Supply Chain Checks

Suppliers and labour providers should be vetted for recruitment practices, worker welfare standards and compliance with UK regulations.

Site-Level Monitoring

Regular checks help identify issues early. Supervisors can speak with workers during daily tasks, observe group behaviour and review how teams are organised. Unplanned visits and routine audits provide a clearer picture of working conditions.

Clear Reporting Routes

Workers need safe ways to raise concerns without fear. Anonymous channels, private conversations and clear instructions on who to contact support early reporting.

Training for Supervisors and Managers

Supervisors must recognise signs of exploitation and know how to act. Modern slavery awareness can be scheduled regularly with construction safety courses to ensure everyone understands that its prevention is just as important as health and safety compliance. 

What To Do If You Suspect Modern Slavery

When concerns arise, contractors must act carefully. The priority is keeping the worker safe while reporting information through the correct channels.

Protecting the Worker

Direct confrontation with suspected offenders may increase danger. Supervisors should avoid any action that exposes the worker to retaliation. Instead, they should observe, record concerns and follow internal procedures.

Escalating to Authorities

Concerns should be passed to the Modern Slavery Helpline or the police where immediate danger is present. Clear records of what was seen or heard help authorities act. Contractors should support any investigation by providing documentation and access to site information.

Building a Culture That Prevents Exploitation

Strengthening workplace culture reduces modern slavery risks. When workers feel secure and valued, they are more likely to speak up. A culture of openness encourages early intervention.

Consistent Supervision

Visible supervision helps prevent coercive behaviour. Managers who know their teams are better placed to spot unusual patterns such as workers arriving together, being managed by unauthorised individuals or avoiding eye contact.

Fair Employment Practices

Clear payslips, reliable contracts and control of personal documents by the worker help build trust. Contractors should work with agencies that avoid recruitment fees and provide transparent job terms.

Worker Engagement

Regular meetings offer a platform for workers to express concerns about pay, hours or living conditions. Engagement helps management understand how labour is organised on the ground.

Collaboration Across the Supply Chain

Contractors can build stronger protection by working with suppliers, clients and labour providers. Shared protocols, aligned checks and open communication reduce blind spots across projects.

When Internal Systems Need Improvement

Sometimes gaps appear in policies or practices. Contractors must review and update procedures when risks increase or after an incident.

Reviewing Reporting Procedures

If workers do not use reporting routes, contractors may need clearer instructions or additional confidential channels.

Updating Supplier Requirements

Supply chain contracts may need stronger clauses on recruitment, living conditions or worker access. Suppliers who fail to meet expectations should be reviewed or replaced.

Strengthening Site Inductions

Inductions should outline worker rights, reporting routes and expected behaviour. Clear guidance reduces confusion and supports new workers who may be unfamiliar with UK labour rules.

Conclusion

Modern slavery remains a real risk across the construction sector. Contractors who implement strong oversight, act on warning signs and create open workplaces reduce harm and avoid legal and reputational damage. Consistent checks, worker engagement and responsible supply chain management make modern slavery harder to hide. A safe and transparent site not only protects vulnerable workers but also strengthens the quality and reliability of every project delivered.