Certificate of Sponsorship (CoS): How to check if a CoS is Genuine or Fake?

Certificate of Sponsorship (CoS): How to check if a CoS is Genuine or Fake?

By Dr Ikram Hasan· Reviewed by Md Lutfur Rahman, FCILEx, Founder and Managing Director, WPC Group

Category: Compliance

Updated05 Oct 2026

What changed: Replaced checks based on the format of the CoS number, licence number and expiry date, which the Home Office does not publish, with checks based on the rules: who pays for a CoS, the bar on Defined CoS for overseas care roles, the register of sponsors and the 3-month time limit.

First published 21 Nov 2023

Table of Contents

What is a Certificate of Sponsorship (CoS)?

A Certificate of Sponsorship (CoS) is a crucial document in the immigration process for foreign workers coming to the UK. It is an electronic record that is issued by approved sponsors to workers they want to hire. The workers then use the CoS to apply for their work visas. However, in today's world where fraudulent activities are on the rise, it's essential to ensure the CoS you receive is genuine. In this blog, we'll guide you through the process of checking the authenticity of a Certificate of Sponsorship.

 

Understanding the Importance of a Genuine CoS

A genuine CoS is not only vital for your visa application but also for ensuring that your job offer and employment are legitimate. An application that relies on a fake or improperly assigned CoS will be refused. If you have already been granted permission on one, the Home Office can shorten it to 60 days, or cancel it outright if you were actively involved, in which case you must leave the UK immediately.

 

How to Verify the Authenticity of a CoS

 

  1. Never pay for a Skilled Worker CoS: The sponsor pays the CoS fee. For a Skilled Worker CoS assigned on or after 31 December 2024, a sponsor must not ask you to pay any part of it or any cost linked to it, and the Home Office will normally revoke the licence of a sponsor that does. The same ban covers Global Business Mobility, Minister of Religion, International Sportsperson, Scale-up and Seasonal Worker certificates assigned on or after 9 April 2025. Whatever the payment is called, if you are asked to pay for a Skilled Worker CoS the offer is either a scam or a breach of the rules. Do not pay.
  2. An overseas care job cannot come with a CoS: A Skilled Worker applying from outside the UK needs a Defined CoS, and none can be issued for care workers (occupation code 6135) or senior care workers (6136). If you are outside the UK and are offered a care job with a CoS, that certificate cannot lead to a visa.
  3. Verify the Sponsor Licence: The first step is to ensure that the sponsor who issued the CoS has a valid sponsorship licence. You can verify this by checking the Home Office's official website - Register of licensed sponsors. You can also check on WPC Sponsor Licence Checker whether the organisation’s licence is active.  Some companies held a licence in the past that is no longer active. The register does not show licence numbers and the Home Office publishes no format for them, so a licence number proves nothing. Check instead that the route on your CoS is listed for that organisation and that it is A-rated. A B-rated sponsor cannot assign a CoS to a new worker. It's essential to confirm that the sponsor's details match the information on the CoS.
  4. Check Your Personal Details: Examine the CoS for any discrepancies in your personal information. Ensure that your name, passport number, and other details are correct.
  5. Check the CoS Number: Every genuine CoS has a unique reference number. The reference number is all you need to apply. The Home Office publishes no format for it, so its length or first letter cannot tell you whether it is genuine.
  6. CoS expiry date:  You must use the CoS in a visa application within 3 months of the date it was assigned, and you cannot apply more than 3 months before the start date on it. A date on the certificate proves nothing on its own, because a fraudster can copy any date.
  7. Check the job start and end date: When reviewing a Certificate of Sponsorship (CoS) for a skilled worker role, confirm that the job's start and end dates match those outlined in your job offer. A Skilled Worker CoS can cover up to 5 years. Other routes have their own maximum periods, and a Scale-up CoS has no end date at all, so a short period does not by itself make a CoS invalid.
  8. Confirm the Job Details: Validate the accuracy of the job details on the CoS against your original job offer. Confirm that the job title, occupation code, salary, and other terms align with your offer and adhere to regulations. Cross-reference the occupation on the Home Office website to ensure that the job title, and salary rate correspond to the Skilled worker: eligible occupation code and going rates. Additionally, confirm that the job description matches the job title on the CoS by referring to the ONS website.
  9. Contact the Sponsor: You can also contact your sponsor directly to confirm the genuineness of the CoS by checking their SMS system. They should be able to provide you with information about the document and address any concerns. Use contact details you have found yourself, for example on the employer's own website or through Companies House, not the phone number or email address in the message that brought you the offer.

 

Ensuring the authenticity of your Certificate of Sponsorship is crucial for a successful and legal immigration process in the UK. Following these steps can help you steer clear of common errors. If in doubt, seeking guidance from legal experts can safeguard your immigration status, allowing you to embark on your journey to work in the UK with confidence. 

How Can WorkPermitCloud Help?

WorkPermitCloud (WPC) is your comprehensive solution for Certificate of Sponsorship (CoS) services. By designating WPC as a Level 1 user within your organisation, you unlock a range of services to streamline your CoS processes. We can assist with assigning CoS, issuing CoS, and handling correspondence with the Home Office. Trust WPC for efficient and effective CoS management, ensuring a seamless experience for your organisation.  

Contact us today at info@workpermitcloud.co.uk

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Legal Disclaimer

The content of this article is intended for general informational purposes only and does not constitute legal advice. Every reasonable effort has been made to ensure the accuracy of the information at the time of publication; however, laws and regulations are subject to change, and interpretations may vary. The information presented is valid only as of the date of publication. WorkPermitCloud Ltd makes no warranties, express or implied, regarding the completeness or accuracy of the information provided. We accept no liability for any loss or damage arising from reliance on this content. For personalised legal advice tailored to your circumstances, we recommend consulting a qualified legal professional.

CONTACT AN ADVISER

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Md Lutfur Rahman, FCILEx

Immigration Advisor and Commissioner of Oath

Managing Director

Work Permit Cloud Limited

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