GOV.UK
Class 1 Structural Overview from 6 April 2003: Changes to the deferment process from 6 April 2003: Unofficial Deferment
Some employees defer payment of their Class 1 NICs in some of their employments withoutauthority from Deferment Services. This is commonly referred to as unofficial deferment.
Employers who continue to operate unofficial deferment should be advised to obtain fromtheir employees a deferment certificate. Any underpayment arising because of unofficialdeferment remains the responsibility of the employer.