This deadline is relevant to small employers only. As a small employer with income tax, national insurance and student loan deductions of less than £1,500 a month you are required to make payment to HMRC of the income tax, national insurance and student loan deductions on a quarterly basis.
Where the payment is made electronically the deadline for receipt of cleared payment is 22nd October 2018. In year interest will be charged if payment is made late. Penalties also apply.