No, you cannot start a business on a student visa because you are not permitted to be self-employed or do business activity. However, there are some limited activities you can do.
So you cannot:
- Register with HM Revenue & Customs as self-employed;
- Work for companies in which you are the controlling shareholder;
- Work for companies in statutory roles, such as a director;
- Trade or establish a trading presence (including test marketing);
- Work for a business in which you have a financial or other significant beneficial interest in a capacity other than as an employee, for example:
- if you set up a business as a sole trader or under a partnership arrangement and that business is either trading or establishing a trading presence;
- if you are employed by a company in which you hold shares of 10% or more (including where the shares are held in a trust for you); or
- if you work for a company where you also hold a statutory role, such as a director.
However, you are permitted do certain pre-business activities as a student (which are not considered to be engaging in business activity):
- Carrying out preliminary activities such as writing business plans or negotiating contracts; and
- Incurring pre-trading costs with a view to deciding whether to start your business.
Also, you are permitted to do business activity if you are endorsed by a university and have applied for your start-up visa (but there has not been a decision yet). This is assuming your visa was granted on or after 1 October 2019.
Now on most student visas you can be employed and work (during holidays and up to 20 hours a week during term time), but this is not the same as being self-employed, or doing the kinds of business activity I have described.