Once a sponsor is satisfied that the student has met the necessary criteria for attendance on a particular course of study, it will issue the applicant a ‘Certificate of Acceptance of Studies’ (normally referred to as a CAS). The CAS is an electronic document that contains details about the course as well the applicant’s personal details. It also provides important information that will be required for the visa application and defines some of the supporting documents that will need to be sent with the application. A CAS must be issued before a Tier 4 application is submitted and can only be used once. 

If, for example, there is a problem and a Tier 4 application is refused, then the Tier 4 sponsor will need to issue a new CAS before a fresh application can be made. Once a CAS has been issued it remains valid for 6 months. The CAS will specify the start date of the course and therefore the earliest date that a Tier 4 visa can be applied for. Applicants cannot submit a Tier 4 application more than three months before the start date of their course of study.