What is an Undefined Certificate of Sponsorship?
An Undefined Certificate of Sponsorship (Undefined CoS) allows UK sponsor licence holders to sponsor Skilled Workers who are already in the UK and eligible to switch or extend their permission. Assigning an Undefined Certificate of Sponsorship correctly is essential, as mistakes can lead to visa delays, refusals and unnecessary costs for employers.
The Business Immigration Team at OTB Legal are often approached by skilled workers and their employers after receiving further information requests on undefined certificates that have been assigned, and more commonly, when a skilled worker application has been refused due to errors on the Certificate that were not resolved before the decision on the application has been made.
This situation causes a great deal of anxiety for the employer. They will have used a precious undefined certificate from their yearly allocation and not managed to secure the employee they desired to assist with their business. Worse still, if the employer only had that one certificate, published timescales on securing an uplift in the yearly allocation currently sits at 18 weeks and whilst priority services are available, they remain heavily oversubscribed.
The refusal of a skilled worker visa also causes significant distress to the employee who may have to leave the United Kingdom to apply for entry clearance or potentially switch into another visa route if they are eligible.
Mistakes are costly both in terms of time and money.
In our experience it is more cost and time efficient to ensure that the certificate that an employer assigns to an employee is correct from the outset.
Common mistakes when assigning an Undefined Certificate of Sponsorship
Immigration Category
There are a number of options in the drop-down menu on the create and assign page of the Sponsor Management System relating to the type of visa that your worker had held before securing their current certificate of sponsorship. These options relate to switching immigration categories; extensions; changes of employment and students switching.
The differences in the options relate to whether the Company will be required to pay the Immigration Skills Charge. Choose the incorrect category and you may needlessly be charged the Immigration Skills Charge or; if one of the Skills Charge exemption categories is confirmed as the route but you are required to pay the charge, this can cause significant delays in the skilled worker visa application process while the Home Office contact the employer to process the additional payment.
Job Title and Type
As a Sponsoring employer, you must ensure that the role has a Standard Occupation Code (SOC) that is eligible for sponsorship and matches the Job Title and Job Description. Assessing job description and SOC codes is a crucial element of assigning a certificate.
The Home Office introduced very significant changes to role eligibility requirements on 22 July 2025, reducing the number of roles that were eligible for sponsorship.
Sponsored workers who were assigned certificates before 22 July 2025 usually benefit from transitional protections, provided they still meet eligibility criteria.
Job roles are now contained in Table 1, 1a, 2, 2aa, 2a, 2b, 3, 3a, 4, 5 and 6 of Appendix Skilled Worker. Navigating these tables can be challenging without a complete immigration history of your potential employee.
Also introduced by the Home Office is the Temporary Shortage List and an updated Immigration Salary List, adding the weight of guidance that must be considered at the point of assignment of the certificate.
Salary
Assigning a certificate with an incorrect salary is an extremely common error.
Changes made by the Home Office on 04 April 2024, 04 April 2025 and 22 July 2025 has added to the burden of assessing the correct salary rates.
There are a number of options in the guidance (options, A, B, C, D, E, F, G, H, I, J and K). Which option is correct depends on the visa status of your employee before you assign the certificate, the job role you are assigning a certificate for, and assessment of the going rates as well as threshold rates for sponsorship for that role. It is unsurprising that so many employers come unstuck that this state.
New Entrants
The new entrant route is for those workers who are new to the employment market and is subject to very specific timescales dependent on the employees’ visa status at the point of assignment. It is very easy to miscalculate the period of sponsorship.
What should you do if you assigned a Certificate incorrectly?
Don’t panic!
Most errors on a certificate can be resolved by the addition of a sponsor note. There are exceptions to this rule, such as an incorrect passport number being entered.
If there are multiple errors that on their own would not affect the validity of a certificate but if they are too numerous to deal with in a sponsor note, you may be advised to withdraw the certificate and assign a new one from your allocation.
I have a Certificate to assign, what can I do?
Contact the Business Immigration Team and OTB Legal and we can advise on and assist you with assigning an Undefined Certificate correctly.
