The United Kingdom is no longer part of the European Union. This changes some rules. Because the United Kingdom has left the European Union due to Brexit and the transition period has expired, it is important for travelers to take a number of things into account after December 31, 2020. Border checks on arrival in the UK can take longer. Keep this in mind. Border controls on departure from the Netherlands will not change. For travelers to the Netherlands, the journey may take longer because border controls are becoming more extensive. 

Britons traveling to or from the Netherlands need a passport that is valid for at least six months on the date of travel. The passport may not be older than ten years. read document with information about renewing your passport. It is possible that the import of certain products (including food and plants, but also excise goods such as tobacco and spirits) from the United Kingdom to the Netherlands and vice versa is no longer allowed. 

This depends on the agreements made by the EU and the United Kingdom. Read in the documents below about importing goods to the Netherlands and about importing goods to the United Kingdom.

Also read: Negative corona test result required at the Belgium border