You must pay any tax and national insurance owed under a PSA by 22 October after the tax year the PSA applies to (19 October if you pay by post). Q2 (2017/18) PAYE/NIC payment due where paid electronically in order to avoid automatic interest charge. Q1 (2018/19) PAYE/NIC payment due where paid electronically in order to avoid automatic interest charge. If you pay by cheque through the post, monthly payments due for PAYE, class 1 NICs and student loan deductions from July 2018. If paying electronically, pay PAYE, class 1 NICs, student loan deductions and deductions from payments to subcontractors for the month up to the 5th of this month.