Certificate of Sponsorship

There are two types of CoS: a defined CoS (allocated by the Home Office in advance for workers who need to apply from outside the UK) and an undefined CoS (assigned by sponsors directly for in-country applications and some other routes). For the Skilled Worker route, the CoS must show the job title, Standard Occupational Classification (SOC) code, salary, and start date. The salary must meet both the general threshold (£41,700 per year since 22 July 2025, or the going rate for the occupation if higher) and the new entrant rate (£33,400) if applicable. Sponsors must retain records and report changes to the worker's circumstances to the Home Office. Misuse of the sponsorship system can result in the sponsor's licence being suspended or revoked.

In practice, the CoS is the single point where a sponsor's compliance record and a worker's application meet, and mistakes on it are expensive because they are hard to unwind. The reference number is only valid for three months from assignment, so a CoS assigned too early can expire before the worker is ready to apply. The details on the CoS must match the visa application exactly: a different job title, a different SOC code, or a salary that reads differently on the payslip than on the certificate will prompt questions and can lead to refusal.

Worked example: a care provider assigns a CoS for a role at £42,000 a year. The worker applies, is granted leave, and starts work. Six months later the employer reduces contracted hours, which drops the effective annual salary below the level stated on the CoS. That is a reportable change and must be notified through the Sponsorship Management System within the required window. If the salary falls below the applicable threshold or the going rate for the occupation, the sponsor must consider whether the worker still qualifies, because continuing to employ them on unchanged terms puts the licence at risk.

The commonest misconceptions: a CoS is not a visa or a job offer that guarantees entry, and the Home Office can still refuse the application on suitability grounds. A defined CoS request can be refused or queried, so employers should not commit to a start date before it is granted. Sponsors also often forget that assigning a CoS starts a chain of continuing duties — record keeping, reporting absences and changes, and cooperating with compliance visits — rather than ending the process.

The CoS is issued under a sponsor licence and is the gateway to the Skilled Worker visa; it does not replace the separate right to work check you must still carry out. Employers should read our guides to certificates of sponsorship and employer sponsor duties before assigning the first one.