This part of GOV.UK is being rebuilt – find out what beta means

HMRC internal manual

National Insurance Manual

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.