Registering for SA - Non-resident individual with no NI number

Hi, I have submitted 2 SA1 forms (print and post versions) for a non-resident person who does not have a NI number. On the 2nd submission to HMRC a cover letter explained that the person did not have a NI number and that the absence of such should not prevent the registration. On both occasions HMRC have replied to the client with a standard letter advising that a NI number is required. Is this correct, if so, are all non-resident persons then required to obtain an NI number before they can be accepted for SA registration? Please can you advise? Thanks Matthew

Hi,
It is possible to register for Self Assessment without a National Insurance number. Details on how to do this can be found here: 
Check how to register for Self Assessment
However, you need a National Insurance number to make sure your NI Contributions and tax are recorded against your name only. If you do not have an National Insurance number you can apply for one here: 
Apply for a National Insurance number 
Thank you