How-to guide: How to assess suppliers for modern slavery risk (UK)

Introduction

This guide will help in-house counsel, procurement teams, sustainability and ethical managers, and risk and compliance teams to assess an organisation’s supply chains for modern slavery risk.

This guide covers the following:

Overview of modern slavery legislation in the UK and elsewhere
Slavery and human trafficking statement
Identifying modern slavery supply chain risks
Monitoring supply chain risks

The objective of this guide is to encourage a risk-based approach for companies in the UK to help reduce modern slavery risk in their supply chains. This guide can be applied to organisations in the public sector, the private sector and voluntary sectors.

It is important for organisations to demonstrate that they take modern slavery seriously and show how they expect suppliers to reduce any negative human rights impacts.

Organisations should establish robust policies and procedures to govern their numerous supplier relationships, and simultaneously ensure that their ethical standards are upheld throughout their supply chains.

This guide can be read in conjunction with Checklist: UK Modern Slavery Act reporting requirements: section 54 (UK).

Section 1 – Overview of modern slavery legislation in the UK and elsewhere

The UK's Modern Slavery Act 2015 (MSA) covers four activities:

human trafficking;
forced labour or compulsory labour;
servitude; and
slavery.

These activities are defined by reference to Article 4 of the European Convention on Human Rights.

1.1 Definitions

There are several useful definitions of servitude, slavery, human trafficking and related terms, including across various international conventions and laws.

They include the definitions below.

Servitude - defined as an obligation to provide services by the use of coercion.
Slavery - defined in International law by the Slavery Convention 1926 as ‘the status or condition of a person over whom any or all of the powers attaching to the right of ownership are exercised’.
‘Modern slavery’ - an umbrella term for different forms of exploitation, such as forced labour, human trafficking, and debt bondage. It is defined by Anti-slavery International as ‘when an individual is exploited by others for personal or commercial gain. Whether tricked, coerced, or forced, they lose their freedom)’.
Forced or compulsory labour – defined as work or services that are exacted from a person under the threat of penalty and for which the said person has not offered himself voluntarily (see International Labour Organization (ILO) Forced Labour Convention 1930).
Human trafficking – defined by Article 3 of the UN Protocol to Prevent, Suppress and Punish Trafficking in Persons (the Palermo Protocol) as ‘the recruitment, transportation, transfer, harbouring or receipt of persons, by means of the threat or use of force or other forms of coercion, of abduction, of fraud, of deception, of the abuse of power or of a position of vulnerability or of the giving or receiving of payments or benefits to achieve the consent of a person having control over another person, for the purpose of exploitation. Exploitation shall include, at a minimum, the exploitation of the prostitution of others or other forms of sexual exploitation, forced labour or services, slavery or practices similar to slavery, servitude or the removal of organs’. The Council of Europe Convention on Action Against Trafficking in Human Beings and the EU Anti-trafficking Directive 2011/36/EU also use this definition.
Supply chains – defined by Investopedia as: a network that connects various companies and individuals in the process of creating and delivering a product to consumers, starting with raw materials and ending with order fulfilment.
Human rights impact assessments (HRIAs) – defined by the Danish Institute for Human Rights as: a process for identifying, understanding, assessing and addressing the adverse effects of the business project or activities on the human rights enjoyment of impacted rights holders such as workers and community members.

Section 2 – Slavery and human trafficking statement

2.1 Section 54 of the Modern Slavery Act

In the UK, section 54 (Transparency in Supply Chains) of the MSA requires commercial organisations to prepare a slavery and human trafficking statement for each financial year to disclose the steps that have been taken, or if no steps were taken, during the financial year to deal with modern slavery risks in the organisation’s supply chains and businesses. This is also known as a ‘modern slavery’ or ‘transparency in supply chains’ (TISC) statement. If an organisation has taken no steps to address modern slavery risks (within its business or supply chains), it has to state this clearly in the statement.

This applies to organisations:

with an annual turnover of £36 million or above;
carrying on a business, or part of a business, in the UK; and
supplying goods or services.

An organisation does not have to be registered in the UK to be caught by the disclosure obligation. It suffices that the organisation carries on a business or part of a business in the UK, along with satisfying the other requirements. In the case of a group of companies, the group can choose to publish one statement, or each company falling under the scope of the MSA can choose to publish a separate statement. If a group chooses to publish one statement, it must:

cover the steps taken to prevent modern slavery in all the organisations within that group that meet the criteria, and their supply chains;
clearly name the parent and subsidiary organisations it is covering; and
be published on the UK websites of all the organisations covered by the statement.

Statements must be published on the organisation’s UK website with a link in a prominent place on the UK homepage. They should also be approved by the board of directors and signed by a director.

To assist businesses in creating this statement and reducing modern slavery risks, the Home Office provides modern slavery guidance. In March 2025, it published updated guidance on Transparency in Supply Chains (TISC Guidance).

To be able to report effectively under the MSA, organisations have to put in place effective human rights due diligence processes to identify and manage modern slavery risks in their operations and supply chains. Specifically, under the MSA, an organisation should report on:

the structure of the business and its supply chains;
its policies concerning slavery and human trafficking;
its due diligence process concerning slavery and human trafficking in its business and supply chains;
the parts of its business and supply chains where there is a risk of slavery and human trafficking, and steps that the organisation has taken to assess and manage that risk;
its effectiveness in ensuring that slavery and human trafficking are not taking place in its business or supply chains, measured against the performance indicators it considers appropriate; and
the training about slavery and human trafficking available to its employees.

2.2 Reporting in other jurisdictions

Companies which are part of a group that operates outside of the UK should note that there are additional reporting requirements prescribed by legislation in other countries, such as:

UK companies may produce separate statements in respect of legislation in different jurisdictions to reflect modern slavery risks and activities, or may choose to report at a global level to comply with reporting obligations using a single statement. In July 2025, the UK Government, jointly with the governments of Canada and Australia, published an International reporting template on modern slavery, forced labour and child labour to serve as a guide for responding to supply chain transparency requirements in these jurisdictions.

2.3 Discussions to strengthen the legal framework

In response to the 2019 Transparency in supply chains consultation, the UK government stated that it may at some point be mandatory (not simply advisable as it had been previously) that organisations report on the following six areas in their statement:

organisation structure and supply chains;
policies in relation to slavery and human trafficking;
due diligence processes;
risk assessment and management;
key performance indicators to measure effectiveness of steps being taken; and
training on modern slavery and trafficking.

On 24 July 2025, the UK Parliamentary Joint Committee on Human Rights published its report on Forced Labour in the UK’s Supply Chains. The report highlighted the need for urgent legislative action, such as establishing mandatory human rights due diligence, introducing an import ban on forced-labour-linked goods, and enabling civil liability and enforcement powers to hold companies accountable.

2.4 Human rights due diligence legislation

While carrying out human rights due diligence is not mandatory under the MSA, UK companies should be aware of the rise in legislation in other countries that makes due diligence mandatory. Some examples include the following:

the French Law on Duty of Vigilance of Parent Companies 2017;
the German Supply Chains Act 2021;
the Swiss Code of Obligations arts. 964 j-l 2020; and
the EU Corporate Sustainability Due Diligence Directive 2024/1760 (CSDDD).

These laws go beyond a requirement to simply report. For instance, the CSDDD imposes an obligation on organisations to identify adverse human rights and environmental impacts, take action to address them, and report on these actions. Even though the CSDDD will be amended by the Omnibus Directive, proposed by the European Commission in February 2025 in an effort to simplify sustainability requirements, the obligation to carry out human rights due diligence remains intact. Alongside the CSDDD, the EU adopted Regulation (EU) 2024/3015 to prohibit products made with forced labour from entering or being exported from the EU market. The Regulation covers all products, without targeting specific companies or industries. Therefore, organisations failing to identify and mitigate modern slavery risk could see their products banned from entering the EU. The Regulation will come into force in 2027.

For further guidance see Checklist: UK Modern Slavery Act reporting requirements: Section 54 (UK).

Section 3 – Identifying modern slavery supply chain risks

There are several reasons listed below as to why your organisation should invest time and resources to identify modern slavery risks.

Legal – identifying and addressing modern slavery issues will help to mitigate against the risk of litigation being brought against it in relation to human rights issues.
Operational – identifying and addressing modern slavery issues will help avoid operational problems from arising, for example, strikes where workers are dissatisfied with their treatment or where goods are retained at port due to international sanctions.
Financial – operational challenges that arise from negative human rights issues cost an organisation more as they try to keep their services and production running. There is also the potential financial impact of litigation.
Access to finance – proactive identification and management of risk is increasingly important to secure finance, because lenders and investors are increasingly considering the human rights and environmental risks associated with potential borrowers.
Reputational – an organisation’s reputation can be severely damaged if modern slavery is occurring in the supply chain and has not been identified or addressed.
Public sector Standards – government contracts and public sector tenders often require compliance with stringent ethical and human rights standards, including modern slavery risk management. Failing to identify and address such risks can result in the loss of valuable public sector contracts.
Customer requirements – many customers are imposing stricter standards and passing down their own legal requirements onto their supply chains. By identifying and addressing modern slavery risks, an organisation ensures compliance with these customer-driven requirements, thereby maintaining critical business relationships and avoiding the risk of losing contracts.

3.1. Modern slavery risk assessment

A good place for an organisation to begin identifying modern slavery risk in its supply chains is a risk assessment at the corporate level. This will allow the organisation to identify issues and address them, lowering the risk of litigation and strengthening compliance with due diligence obligations. The actions taken can be communicated to investors and customers.

There are several possible methods for conducting a desk-based risk assessment of supply chains.

3.1.1 Supply chain mapping

A recommended starting point is to map all the suppliers that the organisation sources materials from and collate information about the locations, functions and risk profiles of the actors within any given supply network.

According to the updated TISC Guidance, ‘supply chain’ refers to both the primary value chain (ie, the goods an organisation sells, or services it delivers) and the secondary value chain (ie, human resource management, catering and cleaning services). It can also include the labour supply chain, which refers to how and from where workers have been recruited to work in the primary and secondary value chain.

The updated TISC Guidance provides further information and case studies on supply chain mapping (pages 18-19).

One example of supply chain mapping is the retailer M&S’s Interactive Supplier Map, which discloses this organisation’s tier one supply chain and is linked to its modern slavery statement.

Once an organisation has completed its risk map, it should prioritise for in-depth assessment and further action those business relationships that pose the highest risks in terms of likelihood and severity.

Prioritisation is key and will be relevant in different stages of an organisation’s risk identification and management process. According to the OECD Due Diligence Guidance for Responsible Business Conduct, ‘where it is not feasible to address all identified impacts at once, an enterprise should prioritise the order in which it takes action based on the severity and likelihood of the adverse impact’. It is therefore critical that an organisation prioritises the most significant risks as part of the mapping process, and devises proportionate steps to mitigate and monitor risk.

At a more granular level, many organisations will map products and materials as far as possible, investigating beyond the first tier of the supply chain to obtain a full view of where raw materials come from.

3.1.2 Categories of risk

There are various categories of risk that should be considered when assessing a supplier or product, for example, geographic or sector risk. Two significant considerations may be the location and sector of the supplier.

Geographic risks

It is important to establish whether any part of an organisation’s supply chain is based in a country or area that has a high risk of modern slavery. Having an awareness and understanding of critical human rights issues and conflicts within sourcing countries and regions is vital for understanding and evaluating vulnerability to modern slavery within the supply chain. This can be achieved at a high level by referring to the Global Slavery Index, which provides an overview of the countries where there is a high prevalence of modern slavery.

Organisations should also consider whether any of the regions that they source from are, or have been, subject to international trade sanctions in relation to forced labour or other human rights abuses.

Sector risk

As listed in the UK Government’s PPN 02/23 – Tackling Modern Slavery in Government Supply Chains – Guidance, certain sectors are known to carry a heightened risk of modern slavery, including:

textiles and garment production, including footwear;
agriculture;
food processing;
fishing and fisheries;
construction;
mining;
logging;
manufacturing and electronics;
logistics, including warehousing and transport;
catering and restaurants;
waste;
transport;
entertainment and the sex industry;
services, including the hospitality, security services, cleaning and catering; and
healthcare, social care.

Organisations should also consider whether the sector has a high proportion of vulnerable workers, such as migrant workers, and whether there is pervasive use of subcontractors in the supply chain. This is important because in some cases – without an organisation knowing – subcontractors do not adhere to an organisation’s standards or policies.

Further information relating to sector risk can be obtained from resources such as the US Department of Labor's List of Goods Produced by Child Labor or Forced Labor.

3.2 Supplier assessments

3.2.1 Risk assessing new suppliers

Organisations should conduct a risk assessment of their business relationships, including suppliers, regularly, and in any case, when they enter a new relationship or market. The following points should be considered when assessing the modern slavery risk when entering a new business relationship with a supplier:

Does a contract carry potential modern slavery risks?
Is the value of the contract significant enough to justify any potential risk of modern slavery? This may be the case where the business is procuring an essential product with an inherently high risk of modern slavery. In such cases, an organisation may have to proceed with the contract, whilst making efforts to mitigate the risk.
How long will this business relationship last, and what is its level of importance within the organisation’s supply chain?
Is there any information available on the risks that the business relationship may contain?
Has the supplier previously had any issues relating to modern slavery?
Has the supplier previously been in the media or questioned on any modern slavery risks?

3.2.2 Engaging with existing suppliers

Beyond the high-level view of a desk-based assessement, organisations can take steps to engage with individual suppliers further to assess the specific modern slavery risk associated with them.

Many organisations require assessments of suppliers to be conducted using self-assessment questionnaires or social audits. These may be used at the outset of a contract when onboarding suppliers or as part of an ongoing risk identification process. Self-assessment questionnaires may be easier to manage as they can be done remotely without having to send an auditor to a factory or site. Depending on time and resources, you may request that suppliers provide documentary evidence with their answers.

Organisations such as Ardea International and Sedex offer self-assessment questionnaires and provide risk categorisation based on the responses. Online supply chain due diligence platforms, such as Taberah, developed by Ardea International, also assist corganisations with assessing the human rights risks posed by their suppliers.

Social audits can provide a valuable overview of the risks in a supply chain. A social audit requires an on-the-ground visit from an organisation’s internal team, or an external professional auditor. However, the limitations of social audits used alone are well documented and organisations such as Shift caution against an over-reliance on this practice. It is imperative for organisations to consider whether alternative risk identification measures should be implemented in conjunction with audits to ensure modern slavery is not hidden from auditors. The TISC Guidance offers insights into the limitations of social audits and their usefulness (page 43).

3.2.3 Stakeholder engagement

Stakeholder engagement is another means to assess the degree of modern slavery risk posed by a supplier.

Stakeholder engagement is the process by which an organisation involves parties who may be affected by the decisions it makes, or can influence the implementation of its decisions, in assessing risk. Engaging with external stakeholders, such as non-governmental organisations (NGOs), local experts, or workers' representatives, can be a valuable tool to identify modern slavery risks specific to the context in which your organisation or its suppliers operate. The TISC Guidance provides further insight on this (page 11).

Internal stakeholders, such as workers, can be invited to engage on human rights concerns through formal or informal stakeholder engagement exercises. This form of stakeholder engagement must be conducted with care, so as not to put the stakeholder at risk of reprisal.

3.2.4 Human rights impact assessments (HRIAs)

To gain a deeper insight into how a business impacts human rights, some organisations may choose to go beyond self-assessments and social audits and choose to conduct HRIAs. These assessments offer a methodology to systematically analyse the potential human rights impacts of an organisation’s business activities on rights holders such as workers, local community members, consumers and others. They complement an organisation’s other due diligence processes rather than replacing them.

HRIAs are an involved process, requiring background research and fieldwork, as well as a large amount of participation of various relevant stakeholders (see below) through face-to-face engagement, such as interviews. These assessments produce a deeper insight into potential negative human rights impacts (such as modern slavery) than a solely desk-based assessment might.

There is also a significant desk-based element to an HRIA, looking at available data and current company processes, alongside external reports and articles to assess where rights holders might be impacted.

The identification of relevant stakeholders depends on the nature of the business and there is no set list; however, it is important that the HRIA assessment process includes the impacted rights holders (eg, workers, supply chain workers, local community members, customers and end-users); the responsible duty bearers (eg, a company operating a business activity, business suppliers and contractors and government authorities); and other relevant parties (eg, individuals or organisations whose knowledge could assist in the assessment of human rights impacts such as trade unions, civil society organisations, local experts, the International Labour Organisation, etc).

Stakeholder engagement should seek to establish how rights holders are affected by an organisation’s operations and business relationships, and the extent to which the organisation’s policies and processes protect them from the principal risks, whether that is discrimination, forced labour, or any other human rights issues.

3.2.5 Grievance mechanisms

Organisations can also assess a supplier’s modern slavery risk by monitoring the frequency and nature of grievances reported by its employees, including whether the employees are aware of the existence of the supplier’s grievance procedure, and how to use it.

The United Nations Guiding Principles on Business and Human Rights (UNGPs) define an operational-level grievance mechanism as:

a formalised means through which individuals or groups can raise concerns about the impact an enterprise has on them—including, but not exclusively, on their human rights—and can seek remedy.

Grievance mechanisms may include whistleblowing hotlines, contact details of internal employees, or third-party channels to raise concerns. These mechanisms serve as a means of proactively identifying potential cases or risks of modern slavery as employees can raise concerns anonymously. Some organisations also extend their own grievance mechanisms to their suppliers’ employees to identify issues further down the supply chain.

Organisations can also use worker voice applications and platforms as an early warning system to identify potential human rights impacts, including modern slavery cases.

The TISC Guidance provides more detail on grievance mechanisms and worker voice (page 42).

3.3 Training

It is important that an organisation’s employees are well-trained to identify modern slavery risks. Some employees will need training specific to their role, for example, those operating in procurement roles within high-risk contexts; however, training to raise awareness of modern slavery risk factors should be provided to all employees. Even those who are unlikely to be exposed to modern slavery can benefit from a basic understanding of what to look for.

Section 4 – Monitoring supply chain risks

Organisations should conduct periodic risk assessments of existing suppliers, to assess any new risks. This could be done within a set timescale and when the organisation becomes aware that the supply chain or a specific supplier presents an increased risk. An increase in risk may occur due to a change in operating context (eg, the COVID-19 pandemic), or where a supplier undergoes a change in circumstances due to a new structure or ownership.

After having assessed modern slavery risks in the supply chain and taken steps to address them, an organisation should then seek to monitor the effectiveness of its anti-slavery strategy.

The UK Government’s official guidance on the MSA advises organisations to put key performance indicators (KPIs) in place. The TISC Guidance provides information on the process to develop KPIs (page 55).

KPIs allow an organisation to monitor the effectiveness of its risk identification and prevention strategies. They can be used to measure the organisation’s progress in mapping or assessing risks within the supply chain, for example, by measuring the:

percentage of suppliers audited;
number of employees trained on identifying modern slavery risk; and
number of stakeholders engaged on identifying modern slavery risk.

This practical resource was produced in partnership with Ardea International.

Additional resources

Organisation for Economic Co-Operation and Development (OECD) - Due Diligence Guidance for Responsible Business Conduct

United Nations - Guiding Principles on Business and Human Rights

International Trade Union Confederation – Global Rights Index 2025

US Department of State - 2025 Trafficking in Persons Report

US Department of Labor - List of Goods Produced by Child Labor or Forced Labor
International Labour Organisation – Combating Forced Labour: A Handbook for Employers & Business
OECD - National Contact Points for Responsible Business Conduct

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Laws

Modern Slavery Act 2015 (UK)