Several European organisations have asked for a so-called grace period for consignments that start their journey before a hard Brexit and arrive after the Brexit date. It is not possible to declare these consignments for export to the UK, as the moment the goods leave the EU, the UK is still an EU Member State.
The customs automation systems will in this case bounce an export declaration for the UK. However, if these goods arrive in the UK, a link with the exit from the EU cannot be retraced which hampers the issue of an import declaration. It is especially true for the goods that are sent from the countries located further away from the major ferry ports; for these goods, the travel may take several days. In case of Brexit on the 31st of January 2020, to launch an export declaration would be already impossible before this date.
Logistical and haulier organisations suggested the European Commission to introduce a grace period to solve these issues. During the Trade Contact Group meeting of the 24th of October 2019, the Commission, however, replied that creating such a grace period was not feasible for them.
For the joint letter of the European organisations, please see here.