PAYE71015 | PAYE operation: aspects of PAYE operation - employee: coding: earnings not assessable or not taxed as PAYE income
From HM Revenue & Customs · PAYE Manual
There are two main types of case where deduction of tax using the normal procedure is impracticable
‘PAYE direct payment’ at PAYE75000 onwards contains advice for cases where an employer is not used to operating PAYE
Where there is an employer but the earnings are not being taxed under PAYE or are not assessable to income tax
If the earnings in the latter case are above the normal minimum amount for deduction of tax
Tell the employer to operate code NT
Use the coding function to enter this code on the individual’s record