Prevention of Illegal Working: 2026 Guide

All UK employers are under a statutory duty to prevent illegal working. This duty applies regardless of the size of the organisation, the sector in which it operates, or whether it sponsors migrant workers under the points-based immigration system. The legal framework is contained primarily within the Immigration, Asylum and Nationality Act 2006, as amended, and is supported by detailed Home Office guidance and a revised Civil Penalty Code of Practice.

Enforcement activity has intensified in recent years. Civil penalties increased significantly in February 2024, compliance visits have become more frequent, and sponsor licence revocations are more readily deployed where systemic failings are identified. Prevention of illegal working is therefore no longer a narrow HR task. It is a core compliance function with financial, operational and reputational implications, shaped by wider Home Office oversight and enforcement priorities through UKVI.

At its centre is the requirement to conduct compliant right to work checks. Where checks are carried out correctly and in accordance with the prescribed Home Office methods, an employer may establish what is known as a statutory excuse. This provides protection against civil liability if a worker is later found to be working illegally. Where checks are not carried out correctly, that protection falls away entirely and the employer may be exposed to a civil penalty and, for sponsors, further compliance action.

What this article is about: This guide provides a 2026 compliance-first overview of the UK’s prevention of illegal working regime. It explains the legal framework, how right to work checks must be conducted, how a statutory excuse operates, the difference between civil and criminal liability, and the practical systems employers should implement to reduce enforcement risk. It should be read as part of an organisation’s wider UK immigration compliance governance and, where relevant, sponsor licence management.

Section A: What Is Prevention of Illegal Working?

Prevention of illegal working is the statutory framework that requires UK employers to ensure that individuals they employ are legally entitled to work in the United Kingdom and to undertake the specific role offered. The duty applies before employment begins and, in cases involving time-limited immigration permission, continues throughout employment.

The obligation is not limited to employers who sponsor migrant workers. It applies universally. Whether an organisation recruits exclusively British nationals or operates a large international workforce, the same legal duty arises.

1. The Legal Framework

The duty stems from sections 15 to 25 of the Immigration, Asylum and Nationality Act 2006, as amended. Under section 15, an employer may be liable for a civil penalty if they employ an individual who is disqualified from employment by reason of their immigration status. Employers should understand how liability is assessed and enforced, including the circumstances in which the Home Office may impose an employer civil penalty.

An individual is disqualified if they:

• Require leave to enter or remain in the UK and do not have it
• Have leave which has expired, been curtailed or revoked
• Hold leave that is invalid
• Are subject to a condition preventing them from doing the work in question

Section 21 of the same Act creates a criminal offence where an employer knowingly employs an illegal worker, or has reasonable cause to believe that the individual is disqualified from employment due to their immigration status.

This framework creates a two-tier enforcement structure: civil liability for failure to comply with right to work requirements, and criminal liability where knowledge or deliberate disregard is present.

2. Who the Duty Applies To

The duty applies to all UK employers, regardless of size or sector. It covers:

• Employees
• Workers
• Some self-employed individuals where an employment relationship exists in substance

The legal test focuses on whether a contract of employment, service or apprenticeship exists. Employers cannot avoid liability by describing a relationship as freelance if, in reality, it amounts to employment.

Where agency workers are engaged, liability may depend on which entity is the legal employer. Clear contractual allocation of responsibility is essential, but it does not override statutory obligations.

3. Policy Objective and Enforcement Direction

The prevention of illegal working regime is designed to remove access to employment as a driver of unlawful residence. The Home Office considers workplace enforcement central to immigration control, with compliance activity led through UKVI.

Since the 2024 civil penalty increases, enforcement trends have shifted in three notable ways:

• Higher financial penalties to increase deterrence
• Greater scrutiny of record-keeping and procedural compliance
• Increased use of sponsor licence suspension and revocation

Home Office compliance officers now routinely assess whether right to work systems are structured, consistent and auditable. Informal or inconsistent checking practices are treated as systemic failings.

Prevention of illegal working is therefore not merely about checking documents. It is about implementing a compliant system capable of withstanding regulatory scrutiny.

Section summary: Prevention of illegal working is a statutory duty under the Immigration, Asylum and Nationality Act 2006. It applies to all employers and is enforced through a civil penalty regime supported by criminal sanctions. Compliance requires structured right to work procedures, not ad hoc checks.

Section A: What Is Prevention of Illegal Working?

Prevention of illegal working is the statutory framework that requires UK employers to ensure that individuals they employ are legally entitled to work in the United Kingdom and to undertake the specific role offered. The duty applies before employment begins and, in cases involving time-limited immigration permission, continues throughout employment.

The obligation is not limited to employers who sponsor migrant workers. It applies universally. Whether an organisation recruits exclusively British nationals or operates a large international workforce, the same legal duty arises.

1. The Legal Framework

The duty stems from sections 15 to 25 of the Immigration, Asylum and Nationality Act 2006, as amended. Under section 15, an employer may be liable for a civil penalty if they employ an individual who is disqualified from employment by reason of their immigration status. Employers should understand how liability is assessed and enforced, including the circumstances in which the Home Office may impose an employer civil penalty.

An individual is disqualified if they:

• Require leave to enter or remain in the UK and do not have it
• Have leave which has expired, been curtailed or revoked
• Hold leave that is invalid
• Are subject to a condition preventing them from doing the work in question

Section 21 of the same Act creates a criminal offence where an employer knowingly employs an illegal worker, or has reasonable cause to believe that the individual is disqualified from employment due to their immigration status.

This framework creates a two-tier enforcement structure: civil liability for failure to comply with right to work requirements, and criminal liability where knowledge or deliberate disregard is present.

2. Who the Duty Applies To

The duty applies to all UK employers, regardless of size or sector. It covers:

• Employees
• Workers
• Some self-employed individuals where an employment relationship exists in substance

The legal test focuses on whether a contract of employment, service or apprenticeship exists. Employers cannot avoid liability by describing a relationship as freelance if, in reality, it amounts to employment.

Where agency workers are engaged, liability may depend on which entity is the legal employer. Clear contractual allocation of responsibility is essential, but it does not override statutory obligations.

3. Policy Objective and Enforcement Direction

The prevention of illegal working regime is designed to remove access to employment as a driver of unlawful residence. The Home Office considers workplace enforcement central to immigration control, with compliance activity led through UKVI.

Since the 2024 civil penalty increases, enforcement trends have shifted in three notable ways:

• Higher financial penalties to increase deterrence
• Greater scrutiny of record-keeping and procedural compliance
• Increased use of sponsor licence suspension and revocation

Home Office compliance officers now routinely assess whether right to work systems are structured, consistent and auditable. Informal or inconsistent checking practices are treated as systemic failings.

Prevention of illegal working is therefore not merely about checking documents. It is about implementing a compliant system capable of withstanding regulatory scrutiny.

Section summary: Prevention of illegal working is a statutory duty under the Immigration, Asylum and Nationality Act 2006. It applies to all employers and is enforced through a civil penalty regime supported by criminal sanctions. Compliance requires structured right to work procedures, not ad hoc checks.

Section B: Right to Work Checks & the Statutory Excuse

Right to work checks are the legal mechanism through which employers comply with their duty to prevent illegal working. The concept is simple: if an employer follows the prescribed Home Office checking process correctly, they may establish a statutory excuse. If they do not, they expose the organisation to civil penalty liability.

The statutory excuse is not automatic. It arises only where the check is conducted in the precise manner required by the current Home Office guidance and, in practice, the employer’s documented processes will be scrutinised by UKVI during enforcement activity.

1. What Is a Right to Work Check?

A right to work check is a prescribed verification process that must be completed before employment begins. It confirms that an individual:

• Has valid immigration permission to work in the UK
• Is permitted to undertake the specific role offered
• Is not subject to a restriction preventing that employment

The check must be completed before employment commences. Conducting it on or after the first working day will not establish a statutory excuse.

Where a worker has time-limited immigration permission, the employer must also conduct follow-up checks before the expiry of that permission to retain protection.

Failure at either stage removes the statutory defence entirely.

2. What Is a Statutory Excuse?

A statutory excuse is a legal defence against civil liability under section 15 of the Immigration, Asylum and Nationality Act 2006.

If an employer:

• Conducts a right to work check using one of the prescribed methods
• Completes it before employment begins
• Retains compliant records

they will not be liable for a civil penalty if the worker is later found to be working illegally.

However, it is critical to understand the limits of the statutory excuse:

• It protects only against civil penalties
• It does not protect against criminal prosecution
• It does not prevent sponsor licence action

If the employer knowingly employs someone illegally, or has reasonable cause to believe they are disqualified from working, criminal liability may still arise regardless of documentation.

Equally, even where criminal liability does not arise, failure to establish a statutory excuse can still result in an illegal working civil penalty. Where the organisation is a sponsor, non-compliance may also trigger enforcement action affecting the sponsor licence.

3. Timing and Retention Requirements

To establish and retain a statutory excuse, employers must:

• Complete the initial check before employment commences
• Conduct repeat checks for workers with time-limited permission
• Retain copies of documents or online verification
• Record the date the check was conducted
• Retain records for the duration of employment and for two years after it ends

The Home Office expects records to be secure, retrievable and capable of being produced during a compliance visit.

In enforcement practice, many civil penalties arise not because an employer failed to check entirely, but because:

• The check was conducted too late
• The wrong prescribed method was used
• Follow-up checks were missed
• Records could not be produced

Right to work compliance therefore depends as much on systems and audit controls as on the initial check itself.

Section summary: A properly conducted right to work check establishes a statutory excuse and protects against civil penalties. That protection is conditional, time-sensitive and method-specific. Errors in timing, method or record retention remove the defence entirely.

Section C: How to Conduct Right to Work Checks in 2026

Right to work checks must be conducted using one of the prescribed methods set out in the Home Office Employer’s Guide. Employers cannot create their own alternative processes. Using the wrong method, even where documents appear valid, will not establish a statutory excuse.

In 2026, there are three recognised methods of conducting right to work checks, together with a separate verification route through the Employer Checking Service in specific circumstances.

1. Online Right to Work Checks (Digital Status Holders)

An online check is mandatory where an individual holds digital immigration status. This includes most migrant workers under the points-based system, such as those on the Skilled Worker visa, and those granted status under the EU Settlement Scheme.

The process requires the individual to generate a share code via the Home Office online service. The employer must then:

• Access the official online right to work checking service
• Confirm that the photograph displayed matches the individual
• Verify that the individual is permitted to undertake the role offered
• Retain evidence of the check, including the date it was conducted

Where status is digital-only, an employer cannot rely on physical documents. Attempting to conduct a manual document check in these circumstances will not establish a statutory excuse. Further practical guidance on digital checks and share codes is available in the Right to Work Share Code guide.

Employers must also check whether any conditions apply, such as limits on working hours or restrictions tied to sponsorship. For sponsored workers, the role must align with the details assigned on the Certificate of Sponsorship.

2. Manual Document Checks (Lists A and B)

Manual checks remain permissible where an individual is entitled to present physical documents under the prescribed lists.

Under this method, the employer must:

• Obtain original documents from List A or List B
• Check them in the presence of the holder (either in person or via live video while in possession of the originals)
• Satisfy themselves that the documents are genuine and belong to the individual
• Check photographs, dates of birth and name consistency
• Confirm that the work offered is permitted
• Copy and retain the documents securely
• Record the date of the check

List A documents establish a continuous statutory excuse. List B documents establish a time-limited statutory excuse and require follow-up checks before expiry. Employers may find it helpful to use a structured right to work checklist to ensure compliance.

Employers are not expected to be forensic document experts. However, where a document is clearly false or does not match the individual, the statutory excuse will not arise.

3. Digital Identity Verification (IDVT via IDSP)

For British and Irish citizens only, employers may use an Identity Service Provider (IDSP) to conduct digital identity verification using Identity Document Validation Technology (IDVT).

Under this route:

• The IDSP verifies the authenticity of the passport
• The employer must confirm the identity of the individual
• The employer must confirm that the photograph matches the person
• The employer must retain the output report

Importantly, the employer retains legal responsibility for the statutory excuse. Use of an IDSP does not transfer liability. This method cannot be used for non-British or non-Irish nationals.

Further guidance on digital verification routes can be found in the overview on digital right to work checks.

4. Employer Checking Service (ECS) and Positive Verification Notices

The Employer Checking Service must be used where an individual cannot provide acceptable documentation but claims to have ongoing permission. Common scenarios include:

• An in-time visa extension application
• A pending administrative review or appeal
• Section 3C leave extending existing permission
• An outstanding EU Settlement Scheme application

If the Home Office confirms the right to work, it issues a Positive Verification Notice. A Positive Verification Notice provides a statutory excuse for six months from the date of issue.

Employers must conduct a repeat ECS check before expiry of the six-month period if the individual’s status remains unresolved.

Failure to use the ECS when required is a frequent cause of civil penalties.

Section summary: In 2026, right to work compliance depends on using the correct prescribed method for the individual’s immigration status. Online checks are mandatory for digital status holders, manual checks remain valid where permitted, IDVT is limited to British and Irish citizens, and the Employer Checking Service must be used where status is pending. Using the wrong route removes statutory protection.

Section E: Preventing Illegal Working Risk in Practice

Compliance with the prevention of illegal working regime does not depend solely on understanding the law. It depends on implementing structured systems that operate consistently across the organisation. In enforcement practice, the Home Office does not simply assess whether a check was conducted. It examines whether the employer has a coherent, auditable process capable of preventing breaches.

Prevention is therefore a governance issue, not an administrative formality.

1. Consistent and Non-Discriminatory Procedures

Right to work checks must be conducted on all workers before employment begins. Employers must avoid practices that single out individuals based on nationality, ethnicity or perceived immigration status. Employers should also be alert to the risk of discriminatory decision-making when conducting right to work checks, including the wider compliance and litigation risks addressed in guidance on discrimination and right to work checks.

A compliant onboarding process should:

• Require right to work checks for every new hire
• Use the prescribed method relevant to that individual’s status
• Avoid insisting on specific documents where alternatives are permitted
• Apply the same timing standards to all recruits

The Equality Act 2010 prohibits discriminatory treatment during recruitment. Selective checking or assumptions about immigration status can expose employers to separate discrimination claims.

Consistency protects against both immigration penalties and employment tribunal risk. In practice, this compliance discipline should form part of wider workforce governance and UK immigration risk management.

2. Record Keeping and Audit Readiness

Enforcement officers expect documentary evidence. Employers must retain:

• Copies of documents or online confirmation
• The date the check was conducted
• Records of any follow-up checks
• Copies of Positive Verification Notices where applicable

Records must be retained for the duration of employment and for two years after employment ends.

Documents should be:

• Securely stored
• Easily retrievable
• Organised in a way that demonstrates systematic compliance

During compliance visits, inability to produce records is treated as failure to establish a statutory excuse, even if checks were originally completed.

3. Visa Expiry Monitoring and Follow-Up Checks

For workers with time-limited immigration permission, employers must conduct follow-up checks before expiry.

Effective compliance systems include:

• Automated visa expiry reminders
• Centralised tracking databases
• Escalation procedures where renewal evidence is not provided
• Prompt use of the Employer Checking Service where status is pending

Missed follow-up checks are one of the most common causes of civil penalties.

Where permission expires and no further leave has been granted, the employer may be required to suspend and ultimately terminate employment. In such cases, fair dismissal procedures must be followed to mitigate unfair dismissal risk.

4. Training and Internal Controls

Those responsible for recruitment and onboarding must be trained in:

• The correct prescribed checking methods
• Identifying digital-only status and share code pathways
• Understanding work restrictions
• Recognising when to use the Employer Checking Service

Regular internal audits should test:

• Whether checks are completed before start dates
• Whether the correct method was used
• Whether records are complete
• Whether follow-up checks are diarised

For sponsor licence holders, right to work compliance should be aligned with sponsorship compliance monitoring, including responsibilities linked to the sponsorship framework and ongoing licence governance. Sponsor teams should also ensure appropriate controls exist around certificate allocation and tracking, including oversight of defined and undefined CoS and the issuing of a Certificate of Sponsorship where required.

5. Responding to Home Office Enforcement

If the Home Office conducts a compliance visit or issues a civil penalty notice, employers should:

• Review whether a statutory excuse exists
• Assess whether representations or objections should be submitted
• Ensure cooperation without volunteering inaccurate or speculative information
• Conduct an immediate internal compliance review

Where sponsor licence action is threatened, early specialist advice is often critical. In cases involving serious compliance concerns, sponsors may also need to implement corrective measures consistent with a wider UKVI action plan.

Section summary: Preventing illegal working requires structured systems, consistent onboarding procedures, reliable visa tracking and trained personnel. Employers who treat right to work checks as a governance function are significantly better positioned to withstand enforcement scrutiny.

Prevention of Illegal Working FAQs

Employers frequently encounter recurring areas of uncertainty when applying the prevention of illegal working regime in practice. The following answers address common compliance questions in line with current Home Office guidance and enforcement practice.

1. What is prevention of illegal working?

Prevention of illegal working refers to the statutory duty on UK employers to ensure workers have valid immigration permission before and during employment. The duty arises under the Immigration, Asylum and Nationality Act 2006 and is enforced through civil and criminal sanctions.

2. What is a right to work check?

A right to work check is the prescribed process employers must follow before employment begins to verify an individual’s legal entitlement to work. The check must be carried out using one of the approved methods: online verification, manual document inspection or digital identity verification (where applicable). Employers can support consistency by using a structured right to work checklist and ensuring process discipline across hiring teams.

3. What is a statutory excuse?

A statutory excuse is a legal defence against civil liability for employing an illegal worker. It arises where the employer has conducted a compliant right to work check before employment starts and has retained the required records.

It protects against civil penalties only. It does not protect against criminal liability where knowledge or reasonable cause to believe illegal working exists.

4. Can an employer be fined if they did not know a worker was illegal?

Yes. If the employer failed to conduct a compliant right to work check, they may be liable for a civil penalty even if they were unaware that the individual lacked permission to work.

Knowledge is not required for civil liability.

5. What are the maximum civil penalties in 2026?

The maximum civil penalties are:

• Up to £45,000 per illegal worker for a first breach
• Up to £60,000 per illegal worker for repeat breaches within three years

The actual penalty imposed depends on the Home Office severity assessment under the Civil Penalty Code of Practice and whether the employer can establish a statutory excuse. Employers may wish to review their exposure and options where a civil penalty is threatened or issued.

6. Does a statutory excuse prevent criminal prosecution?

No. Criminal liability arises where an employer knowingly employs an illegal worker or has reasonable cause to believe that the individual is disqualified from employment. In such cases, a statutory excuse will not provide protection.

7. When must follow-up right to work checks be conducted?

Follow-up checks must be completed before the expiry of time-limited immigration permission or before the expiry of a Positive Verification Notice issued by the Employer Checking Service.

Failure to conduct a repeat check removes the statutory excuse.

8. Does the duty apply to agency workers?

Responsibility generally rests with the organisation that is the legal employer. However, contractual arrangements should clearly allocate responsibility, and businesses engaging agency workers should ensure that compliant checks are being conducted.

9. Can an employer dismiss a worker who loses their right to work?

If a worker no longer has permission to work, the employer may need to terminate employment. However, fair procedures should be followed to reduce the risk of unfair dismissal claims, particularly where the employee has qualifying service.

Conclusion

Prevention of illegal working is one of the most actively enforced areas of UK immigration law. The statutory framework places a clear and ongoing duty on all employers to ensure that individuals they employ have valid permission to work and are permitted to undertake the specific role offered.

Since the increase in civil penalties in 2024, enforcement has become more financially punitive and procedurally rigorous. Civil penalties can reach £60,000 per worker for repeat breaches. Criminal liability may arise where knowledge or reasonable cause to believe illegal working exists. For sponsor licence holders, enforcement action can extend to suspension or revocation, with serious operational consequences and potential disruption to recruitment pipelines reliant on sponsorship.

The statutory excuse remains the employer’s primary defence, but it is strictly conditional. Protection depends on:

• Conducting right to work checks before employment begins
• Using the correct prescribed method
• Completing follow-up checks for time-limited permission
• Retaining compliant records
• Maintaining consistent, non-discriminatory procedures

Right to work compliance is no longer a reactive safeguard. It is a proactive governance requirement embedded within recruitment, HR systems and sponsor licence management, with Home Office oversight increasingly exercised through UKVI.

Employers that implement structured processes, robust monitoring and regular internal audits are significantly better placed to withstand Home Office scrutiny and avoid costly enforcement action. Where sponsorship is central to resourcing, compliance controls should also align with the operational requirements of maintaining a sponsor licence and, where relevant, the proper use of a Certificate of Sponsorship.

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