What are the consequences of Brexit if I reside in the United Kingdom to study there?
When you start a study before 31 December 2020 and continue your study beyond that date, you can apply for a “pre-settled status” via the EU Settlement Scheme until 30 June 2021 (see question 2). It is in your own interest to register as soon as possible.
If you wish to reside in the United Kingdom to study there starting from or after 1 January 2021, you will have to meet the specific requirements that will then apply to EU citizens under the new British immigration laws. The British Home Office made an announcement about this.
While you can stay in the UK visa free for up to 6 months you are in principle not allowed to study or work during that time. You have to take into account the list of activities allowed during a visit. There are nevertheless limited exceptions, such as exchange semesters at an accredited UK institution.
Internships, even unpaid, of any duration require you to apply for a visa.
In most cases you will therefore have to apply for a specific visa for study purposes under the new points-based immigration system. For more information on the modalities of this visa, please consult the general and specific sheet available on the website of the British Home Office.
Please note that your application for a study visa must certainly be accepted before your departure to the United Kingdom. You cannot first travel to the UK and then file the application afterwards.