Hi,
Please refer to:
CWG2: further guide to PAYE and National Insurance contributions.
At section 4.6.6 you will find three conditions.
If these are met, there is no liability to tax and National Insurance in the UK, and therefore, you do not need to add the employee to payroll.
If you do, then operate tax code "NT" and category letter "X" for National Insurance.
If the conditions are not met, add the employee on to payroll as normal.
However, you can ask the employee to send us form P85 if they have been resident in the UK before. This will confirm their tax code. Similarly, you can speak to an International Caseworker for National Insurance on 0300 200 3500 to clarify their National Insurance position.
Thank you.