HR & Workforce · Mandatory · Annual

Modern Slavery Supply Chain Statement

An annual statement required by the Modern Slavery Act 2015 for organisations with turnover over £36 million.

Last reviewed: 29 March 2026 — This guide reflects UK law as of this date. Modern Slavery Act 2015 remains current with no amendments enacted as of 29 March 2026. Next scheduled review: 29 March 2027.

Legal basis	Modern Slavery Act 2015 (MSA) section 54
Applies to	Commercial organisations with an annual turnover of £36 million or more that supply goods or services and carry on business (or part of a business) in the UK
Six required areas	Organisation structure, policies, due diligence, risk areas, KPIs, and training (s.54(5) MSA 2015)
Publication	Must be published annually on the organisation's website with a prominent link from the homepage, within 6 months of the end of the financial year, approved by the board, and signed by a director
Construction risk	Construction is one of the highest-risk sectors for modern slavery — migrant labour, multi-tier subcontracting, labour-only supply chains, and cash-in-hand payments all increase vulnerability
Reporting	Suspected modern slavery should be reported to the Gangmasters and Labour Abuse Authority (GLAA) or the Modern Slavery Helpline: 0800 0121 700

1. Modern Slavery Statement

A modern slavery statement is not a document that should sit in a drawer or exist solely to satisfy a legal obligation. It is a public commitment to looking hard at your supply chain — at every tier, every labour provider, every subcontractor — and taking genuine, practical steps to ensure that no one in that chain is being forced to work, trafficked, held in servitude, or exploited. In construction, where complex and multi-layered subcontracting arrangements are the norm, this requires genuine due diligence, not box-ticking.

Section 54 of the Modern Slavery Act 2015 requires every commercial organisation with an annual turnover of £36 million or more that supplies goods or services and carries on business (or part of a business) in the United Kingdom to prepare a slavery and human trafficking statement for each financial year. The statement must set out the steps the organisation has taken during the financial year to ensure that slavery and human trafficking is not taking place in any part of its own business or in any of its supply chains — or, if the organisation has taken no such steps, it must state that fact.

Construction is one of the sectors most vulnerable to modern slavery. The Gangmasters and Labour Abuse Authority (GLAA) has conducted numerous investigations into labour exploitation in construction, uncovering cases where migrant workers have been recruited from overseas with promises of good wages and accommodation, only to arrive and find themselves housed in overcrowded and substandard conditions, paid well below the minimum wage (or not paid at all), forced to work excessive hours, and controlled through debt bondage, confiscation of identity documents, and threats of violence. Multi-tier subcontracting, the use of unregulated labour providers, and cash-in-hand payment practices all create the conditions in which exploitation can flourish and remain hidden.

Report suspected modern slavery immediately

If you suspect that modern slavery or labour exploitation is taking place on a construction site or within a supply chain, report it immediately. The Gangmasters and Labour Abuse Authority (GLAA) is the lead enforcement body for labour exploitation in the UK and can be contacted through its website. The Modern Slavery Helpline (0800 0121 700) is a confidential service operated by the charity Unseen and provides advice, support, and a mechanism for reporting concerns. You can also report anonymously through Crimestoppers on 0800 555 111. Do not attempt to investigate or intervene yourself — this could put victims at further risk.

2. Recommended Content

Section 54(5) of the Modern Slavery Act 2015 sets out six areas that a statement may cover. Although the legislation uses the word “may,” the government's statutory guidance makes clear that organisations should address all six areas. A statement that does not address these areas is unlikely to demonstrate genuine due diligence and may attract scrutiny from investors, clients, and enforcement bodies.

Area	What to include
1. Organisation structure	A description of the organisation's structure, its business activities, and its supply chains. For a construction company, this should include the types of projects undertaken (residential, commercial, infrastructure), the typical supply chain structure (main contractor, subcontractors, labour providers, material suppliers), the number of directly employed workers and the number of subcontracted workers, and the geographical locations where the organisation operates.
2. Policies	The organisation's policies in relation to slavery and human trafficking. This should include a standalone modern slavery policy, a whistleblowing policy that specifically covers how workers (including agency and subcontracted workers) can report concerns about exploitation, a recruitment policy that covers right-to-work checks and fair recruitment practices, and a supplier code of conduct that sets out the standards expected of subcontractors and labour providers.
3. Due diligence	The due diligence processes the organisation has in place to identify and address modern slavery risks in its business and supply chains. In construction, this should include how subcontractors and labour providers are vetted before appointment, how the organisation verifies that workers on its sites have the right to work in the UK and are being paid at least the National Minimum Wage, how labour-only subcontractors and gang labour providers are monitored, and how the organisation audits compliance with its supplier code of conduct.
4. Risk areas	An assessment of the parts of the business and supply chains where there is a risk of slavery and human trafficking taking place. Construction-specific risks include: the use of migrant labour (particularly from countries with high emigration and known trafficking routes), multi-tier subcontracting where the main contractor has limited visibility of the workforce at lower tiers, labour-only supply chains, cash-in-hand payments, overcrowded or employer-controlled accommodation, and work in remote locations.
5. KPIs	The key performance indicators the organisation uses to measure the effectiveness of its efforts to ensure that slavery and human trafficking is not taking place. Examples include: the percentage of subcontractors and labour providers that have completed a modern slavery questionnaire, the number of supply chain audits conducted, the number of concerns reported through the whistleblowing mechanism, the number of right-to-work checks carried out, and the percentage of relevant staff who have completed modern slavery awareness training.
6. Training	The training about slavery and human trafficking available to the organisation's staff. This should cover who receives training (procurement staff, site managers, HR, directors), the content of the training (how to recognise the signs of exploitation, how to report concerns, the organisation's responsibilities under the MSA), and how often the training is refreshed. Front-line site staff should receive awareness training on recognising the signs of modern slavery among workers on site.
Approval	The statement must be approved by the board of directors (or equivalent management body) and signed by a director (or equivalent). This ensures senior-level accountability for the content of the statement and the steps described in it.
Publication	The statement must be published on the organisation's website with a link in a prominent place on the homepage. It must be published within 6 months of the end of the organisation's financial year. Organisations are also required to submit their statement to the government's modern slavery statement registry.

3. Common Mistakes

Statement signed by a director who is no longer on the board

The Modern Slavery Act requires the statement to be signed by a director (or designated member or partner). If the statement is signed by a director who has since left the organisation, the statement is not compliant. This commonly occurs when organisations copy last year's statement with minor updates but fail to check that the signatory is still a serving director. The statement must be approved by the current board and signed by a current director before publication. This is not a mere formality — it is the mechanism by which the Act ensures board-level accountability for the organisation's response to modern slavery risks.

Statement contains aspirational language but no evidence of due diligence

A modern slavery statement that says the organisation “is committed to eradicating modern slavery” and “does not tolerate exploitation in any form” but contains no evidence of what the organisation has actually done during the reporting period is not compliant with the spirit or the purpose of the Act. The statement must describe the specific steps taken — not the steps the organisation hopes to take, intends to take, or aspires to take. This means documenting the audits conducted, the training delivered, the concerns reported and investigated, and the changes made to procurement processes. An aspirational statement with no substance is worse than no statement at all, because it creates a false impression of compliance.

Not publishing the statement within 6 months of the financial year end

The government's statutory guidance is clear that the modern slavery statement should be published as soon as reasonably practicable after the end of the financial year, and in any event within 6 months. An organisation with a financial year ending on 31 March must publish its statement by 30 September at the latest. Failure to publish on time is a compliance failure that is visible to investors, clients, and enforcement bodies. The Home Office maintains a public registry of modern slavery statements, and organisations that are late or non-compliant are identifiable. In construction, major clients increasingly require evidence of a compliant modern slavery statement as a condition of tender.

4. Frequently Asked Questions

Does the Modern Slavery Act apply to smaller subcontractors below the turnover threshold?▾

The statutory duty under section 54 of the Modern Slavery Act 2015 to publish a modern slavery statement applies only to commercial organisations with an annual turnover of £36 million or more. However, this does not mean that smaller subcontractors can ignore modern slavery. First, the criminal offences of slavery, servitude, forced or compulsory labour, and human trafficking under sections 1 and 2 of the Act apply to everyone, regardless of turnover. Second, main contractors and tier 1 subcontractors that are subject to the reporting duty increasingly require their supply chain — including smaller subcontractors — to demonstrate compliance with modern slavery standards as a condition of appointment. This is typically achieved through a modern slavery questionnaire, a supplier code of conduct, and audit rights in the subcontract. Third, the government has indicated that the turnover threshold may be lowered in the future, bringing more organisations within scope. Smaller subcontractors should therefore be prepared to demonstrate their approach to preventing modern slavery, even if they are not yet legally required to publish a statement.

What is the difference between modern slavery and labour exploitation?▾

Modern slavery and labour exploitation exist on a spectrum, and the boundary between them is not always clear-cut. Modern slavery, as defined by the Modern Slavery Act 2015, encompasses slavery (where one person owns another), servitude (where a person is obliged to provide services and cannot change their condition), forced or compulsory labour (where a person is made to work under threat of penalty and has not offered themselves voluntarily), and human trafficking (where a person is recruited, transported, or harboured for the purpose of exploitation). Labour exploitation that does not reach the threshold of modern slavery may still be unlawful — for example, paying below the National Minimum Wage, making unlawful deductions from wages, failing to provide adequate rest breaks, or subjecting workers to harassment or unsafe working conditions. The Gangmasters and Labour Abuse Authority (GLAA) has the power to investigate both modern slavery offences and labour exploitation offences. In construction, the indicators of exploitation include workers who appear frightened or withdrawn, who do not have their own identity documents, who live in accommodation provided and controlled by their employer, who are transported to and from site by their employer and cannot leave independently, who are paid significantly below market rates (or not at all), and who appear to be under the control of another person.

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