How does the payment of customs duties work when shipping to the UK?

In case you ship your parcels under INCO term DAP, Billing term NP (Not Paid: recipients pays all costs) your customer will have to pay customs duties prior to delivery. DPD UK will send a secure digital payment request per email or sms. Without payment of these costs + admin fee (£5) within 5 days the parcel will be returned to you.