Certificate of Sponsorship Explained

There are two types of Certificate of Sponsorship:

• Defined CoS — Used when the worker is applying from outside the UK (entry clearance). Defined CoS must be allocated from a pool — there is a monthly allocation process for some occupation codes. The sponsor requests a defined CoS from UKVI, which is checked before it is issued.
• Undefined CoS — Used when the worker is already in the UK and is applying to extend, switch, or vary their leave in-country. Undefined CoS are assigned directly by the sponsor without prior UKVI approval, subject to the annual allocation limit.

Both types contain the same core information: the worker's personal details, the job title and SOC code, the salary, the start date, and the sponsor's details. Both are valid for three months from the date of assignment (defined CoS) or expiry (undefined CoS) — the visa application must be submitted within this period.

The Certificate of Sponsorship contains the following information that is critical to the visa application:

• The occupation code (SOC code) — This determines the going rate salary threshold and whether the role qualifies for the Skilled Worker route;
• The job title and description — Must accurately reflect the actual duties of the role;
• The gross salary — Must meet both the general Skilled Worker salary threshold and the specific going rate for the occupation code;
• The start date and end date — The visa will be issued to cover this period;
• The sponsor's licence number and name.

Any errors on the CoS must be corrected before the visa application is submitted. Once the visa application has been submitted, the CoS details cannot easily be changed. If the salary or role on the CoS does not match the actual job, this can be grounds for refusal.

A sponsor can withdraw a Certificate of Sponsorship before the visa is granted — for example, if a job offer is rescinded. If the CoS is withdrawn before the visa application is decided, the application will be refused (as the requirement to hold a valid CoS will no longer be met).

If the CoS is withdrawn after the visa is granted — which can happen if the employment relationship ends — the worker's visa may be curtailed (see the curtailment of leave guide). This gives the worker 60 days to find a new sponsor and apply for a new visa.

Workers should keep a record of their CoS reference number and the details on the CoS, as these will be needed when applying for visa extensions in future. The CoS reference is entered into the visa extension application form.