If you already have a degree and want to study a programme which is at the same or lower level, you’d be classed as having Equivalent or Lower Qualifications (ELQ status).
An example of this is if you already have an MA and you’d like to return and study a BSc, you’d have ELQ status.
ELQ status is allowed but can affect your visa and finances - for example, you may not get Student Finance funding for the new course and if you’re an international student you may not be able to get a student visa.
If you’re self-funding and are allowed to study in the UK, you’re welcome to study as many programmes as you want.
