Understand UK Certificates of Sponsorship (CoS), defined and undefined processes, allocations and common employer errors.

What is a CoS?

A Certificate of Sponsorship is an electronic reference, not a paper certificate. The sponsoring employer assigns it to an eligible worker using the Home Office sponsorship system.

• Choose the correct CoS type

• Check role, pay and work details for accuracy

• Maintain records explaining the sponsorship decision

The record identifies the sponsor, role and employment information used in a visa application.

Defined or undefined?

The type of CoS needed depends on the sponsorship route and the worker’s circumstances, including where an applicant is applying. Employers must use the correct process for the intended role.

If an allocation or defined CoS request is needed, prepare a consistent explanation and supporting information.

Check the role carefully

Occupation codes, duties, salary and job location should align with genuine employment. An inaccurate CoS may cause visa problems and compliance concerns.

Changes to circumstances should be reviewed before assignment or use of a certificate.

Avoid common mistakes

Do not confuse sponsorship permission with immigration approval. Equally, do not assume a previous allocation covers future roles or new kinds of employment.

A short review of the CoS details is often less disruptive than correcting an avoidable error later.

Next steps

Explore a related service below, or book a consultation to discuss your own case.

Official guidance: GOV.UK: sponsor guidance

Explore service: Defined CoS Requests

Explore service: Undefined CoS Allocation

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Related guides

UK Sponsor Licence: How It Works

Sponsor Licence Application Checklist