The introduction of the Student route in October 2020 does not affect existing Tier 4 visas. If you already have a Tier 4 visa you can use it to enter the UK at any point during its validity to continue the studies for which it was issued.
You can also use a valid ("extant") Tier 4 or Student visa to re-enter the UK after your studies have finished, for example if you want to make a new Student route application in the UK for a new course. If you prefer, you can also apply for the new Student visa in your home country.
If you plan to travel to the UK on an extant Tier 4 visa to apply for a Student route visa there, rather than applying for your new Student visa in your home country, you need to make three checks.
First, check that you can apply for under the Student route within the UK anyway (see Making a Student route application in the UK). If not, you will need to apply from your home country.
Second, check that you meet all of these requirements:
- the institution you are returning to study at has a Student sponsor licence, and they have agreed to sponsor you (or continue to sponsor you); and
- you have not been reported to the Home Office as having finished your most recent course early, having interrupted your studies, or having not enrolled. If the institution that sponsored your current Tier 4 or Student visa has reported one of these matters, it is likely that your visa has been cancelled; and
- you are eligible and can meet the requirements to make Student route application from within the UK
Third, carry in your hand luggage evidence to show the Border Force Officer that you will be making a new immigration application before your current permission expires. At the minimum, this would be evidence that you have already been issued a CAS from your new sponsor institution. If you have other evidence, for example some of the documents you will be providing as part of your upcoming Student route application, keep them in your hand luggage for possible checking. The Border Force Officer cannot issue you with a Student visa on arrival, but they can allow you to enter the UK in order to make the application.