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

HMRC internal manual

National Insurance Manual

Class 4 liability: deferment & the annual maximum

Regulations 95 & 100 SS(C)R 2001

To avoid an overpayment of NICs and the need for refund later a contributor can ask to defer any liability to pay Class 4 NICs. Deferment Services within NIC&EO handle all work associated with deferment.