If an import declaration is made to Importers Knowledge and the evidence is not seen to have been in place at the point of import during HMRC audit, the liability for duty and any penalty will fall to the importer.
In some trade agreements, an importer can claim a preference duty rate using information the importer holds that confirm the origin of the goods. This is known as ‘importers knowledge’ and can be used as an alternative to an exporter origin declaration
However, the compliance requirement on the importer is heavy, and the method can easily be mistaken if there is an assumption on the part of the importer that goods being delivered from a country are originating from that country under preference conditions (compliant with a free trade agreement).
Source Strong & Herd