Income: Employment income rules: The amount (if any) by which a payment of Statutory Maternity Pay (SMP), Statutory Paternity Pay (SPP), Statutory Shared Paternity Pay (ShPP) or Statutory Adoption Pay (SAP) exceeds £100 per week
The Tax Credits (Definition and Calculation of Income) Regulations 2002, Reg. 4(1)(h)
This is effectively a disregard of up to £100 for each week of SMP, SPP, ShPP or SAP received in the tax year. Note that where the rate of SMP, SPP, ShPP or SAP received is less than £100 per week, only an amount equivalent to that received in each week of SMP, SPP, ShPP or SAP in the tax year can be disregarded from the total pay and SMP, SPP, ShPP or SAP income for the year. For example, if £80 SMP, SPP, ShPP or SAP is received in any week, only £80 can be disregarded.
This is different from the income tax treatment. All SMP, SPP, ShPP and SAP is included as income for income tax purposes.