You are permitted to work for any employer while you run your new business, but it would make sense to do a job related to your business to help gain further business experience. You are not permitted to work full-time for an employer and neglect your business. Part-time employment is supposed to help you cover day-to-day living costs and initial business setup/running costs until your business is operational and making a profit. Your appointed endorsing body is supposed to guide and monitor you and your business so they will explain the process. Please note that I would not work for employers more than 50% of the working week, meaning that you give your business at least 50% of your time. If you abuse the visa route, your endorsing body can revoke your sponsorship and curtail your visa status.
How can applicants of a startup visa take a part-time job in the U.K.?
I learned recently that applicants of a U.K. startup visa are permitted to work on part-time jobs while in the U.K., in addition to the position at the startup business. Does the startup visa holder need to apply for a separate work permit for the part-time position? Does the part-time position need to be in the same industry as the visa holder’s startup?