If you need to register as self-employed but you don’t have a national insurance (if for example you have just relocated to the UK), usually DWP would hold face to face interviews as part of the process of allocating you a national insurance number. However, due to COVID19, the processing of national insurance number allocations has been suspended, and currently there is no date for when this will restart.
As an interim measure, affected individuals that need to register as self-employed should do so by completing a SA1 form (which you can find by searching on gov.uk). In the “reason for no national insurance number” section, enter that you are unable to obtain one as DWP are not currently holding face to face interviews due to COVID19. In the section “why do you need to complete a tax return” you should complete box “any other reason” as “self-employed”, and include the type of work you are doing.
Once you have been allocated a national insurance number you will need to call the self-employed helpline to register for class 2 national insurance straight away. This is important as it will ensure that your contributions are recorded correctly for future benefit claims.