This deadline is relevant for employers who have provided their employees with benefits for 2016/17. These benefits should have been reported by the 6th July and the amount of the Class 1A employer only NI liability due calculated on the form P11D(b).
Where the payment is made electronically the deadline for receipt of cleared payment is Friday 21st July 2017 unless you are able to arrange a ‘Faster Payment’ to clear on or by Saturday 22nd July. Interest will be charged if payment is made late. Penalties may also apply.