Certificates of Sponsorship (CoS) – Summary & How Lux Nova Immigration Supports Employers
Certificates of Sponsorship (CoS) are a core component of the UK’s sponsored work visa system. A CoS is not merely an administrative reference number, but a formal declaration by a licensed sponsor to the Home Office that a role is genuine, eligible, and meets all skill, salary, and compliance requirements at the time of assignment. Errors in CoS requests or poor allocation planning can lead to visa refusals, recruitment delays, wasted costs, or sponsor licence enforcement action.
There are two types of CoS:
- Defined CoS (DCoS) required for Skilled Worker applications made from outside the UK and approved on a case-by-case basis by the Home Office.
- Undefined CoS (UCoS) used for in-country applications and all other sponsored work routes, issued from an annual allocation granted to the sponsor.
Both require careful planning, accurate evidence, and strict compliance with Home Office guidance.
A Certificate of Sponsorship (CoS) is a mandatory requirement for most UK sponsored work visas. It is a formal declaration to the Home Office that a role is genuine, eligible, and compliant. Errors or poor planning can lead to visa refusals, recruitment delays, or sponsor licence action.
Lux Nova Immigration helps employers secure and manage both Undefined (UCoS) and Defined (DCoS) Certificates of Sponsorship in a way that supports business growth while minimising compliance risk.
We work with businesses to:
- Plan annual UCoS allocations strategically, aligned with recruitment needs
- Prepare strong, evidence-led DCoS requests to meet heightened Home Office scrutiny
- Secure allocation increases efficiently where required
- Ensure CoS are assigned correctly, on time, and with full supporting records
Our approach reduces delays, avoids wasted costs, and protects your sponsor licence so sponsorship works as a business enabler, not a barrier.