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Penalties for Employing Illegal Workers

UK employers must be aware of the law on preventing illegal working. This is set out in sections 15 to 25 of the Immigration, Asylum and Nationality Act 2006 (the 2006 Act).

Illegal working often results in abusive and exploitative behaviour, the mistreatment of illegal or overstayer migrant workers, tax evasion and poor housing conditions. It can also undercut legitimate businesses and have an adverse impact on the employment of people who are lawfully in the UK and on the UK economy.


Who are illegal or overstayer migrant workers?

This includes:

  • Individuals with no visas
  • Individuals with expired visas
  • Students working more hours than permitted to
  • Iindividuals who have made applications to the Home Office after their leave has expired
  • Individuals who work on a visitor’s visa (unless in a Paid Permitted Engagement category)
  • Individuals working outside the permitted employment category

What are the civil penalties for employing an illegal or overstayer migrant?


Under section 15 of the 2006 Act, an employer may be liable for a civil penalty for employing an individual who does not have the right to undertake the work in question. This could result in:

  • Liability of up to £20,000 for each illegal or overstayer migrant employed.
  • Publication of business details by Immigration Enforcement as a deterrent to other employers


Civil defences


An employer may establish a statutory excuse against civil liability by carrying out prescribed document checks before any employment begins.


Prescribed document checks

Employers should:

  1. Obtain the individual’s original identity documents listed in the Home Office guidance as including but not limited to :


  1. Biometric Residence Permits
  2. Residence Cards
  • UK, or Common Travel Area passports
  1. Individuals with the Right of Abode
  2. Naturalisation or Birth Certificates
  3. Check that these documents are valid with the individual present
  4. Copy and keep the documents securely. Record the date of the check.


Employer Checking Service


Employers who are reasonably satisfied that the individual has an outstanding application with the Home Office that was made before their previous leave expired or has an outstanding administrative review or appeal against a Home Office decision can get a Positive Verification Notice which confirms their right to work from the Employer Checking Service (


What are the Criminal penalties for employing an illegal or overstayer migrant?


Under section 21 of the 2006 Act an employer may be prosecuted for the offence of “knowingly employing an illegal worker”. The criminal penalties include:


  • Up to 2 years in prison
  • Unlimited fine


Criminal defences

The statutory excuse of having carried out prescribed document checks before any employment begins is not available where the employer knows that the employment is not permitted.



Our experienced lawyers can help Employers:

  • Challenge any civil penalty notices by way of an appeal
  • Defend any criminal prosecution

We will assist by:

  • Obtaining the complete facts of a case
  • collecting relevant documents
  • advising the best solutions
  • preparing the responses to civil penalty notices
  • prepare any criminal defence
  • submitting the application(s) to the relevant authority
  • communicating with the relevant authority until a decision is made
  • advising about rights and entitlements following a decision
  • providing follow up support and services




DESCARTES SOLICITORS is recognised as one of the leading multi-practice firms in the UK. Our specialist immigration team works closely employers issued with Civil Penalty notices or being prosecuted for employing or knowingly employing an illegal worker.

For advice and assistance in respect of challenging civil penalty notice, appeals or related criminal defence, please contact our lawyers on 02089953556/08445569901 or e-mail



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Illegal working civil penalties: an employer’s guide