NIM01008 | Class 1 Structural Overview: The Primary Threshold ('PT') and the Secondary Threshold ('ST')
From HM Revenue & Customs · National Insurance Manual
Section 5 of the Social Security Contributions and Benefits Act (SSCBA) 1992 and regulations 10 & 11 of the Social Security (Contributions) Regulations 2001 (SI 2001 No 1004)
The Primary Threshold (PT) and Secondary Threshold (ST) represent the points from which payment of NICs arises, as opposed to the point at which entitlement to benefit builds up,which is set by the Lower Earnings Limit (LEL) (NIM01005). The monthly and yearly PT and ST are fixed each year. For guidance on how to calculate the PT and the ST for pay intervals of other than one month or one year, see NIM01010.