This deadline is relevant to small employers and contractors 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.
Postal payments for month/quarter ended 5 April should reach your HMRC Accounts Office by this date.
Where the payment is made electronically the deadline for receipt of cleared payment is Thursday 18th April 2019 unless you are able to arrange a ‘Faster Payment’ to clear on or by Monday 22nd April. In year interest will be charged if payment is made late. Penalties also apply.