What is CHIEF?

The Customs Handling of Import and Export Freight (CHIEF) system records the movement of goods by land, air and sea. It allows importers, exporters and freight forwarders to complete customs formalities electronically and checks for entry errors.

This is the UK Customs computer system. It is old and slow. The plan is to upgrade it to CDS (Customs Declaration System) and this was planned long before BREXIT became a thing. The process is proving to be cumbersome and is already behind schedule.