Packages and parcels from Britain to the European Union will be subject to duty from the turn of the year, the country's Post Office has said.
From 1 January, people in Britain must enclose a customs declaration form with their shipment, the postal service said, and advised customers to follow the new regulations from Tuesday in order to avoid delays.
"Customers posting from England, Scotland and Wales will be required to attach customs declaration forms to all items containing gifts or goods being sent abroad, including to EU destinations," according to a Post Office statement.
Customs declaration forms are not required for goods sent to EU destinations from Northern Ireland.
This is due to the so-called Northern Ireland Protocol agreed with Brussels to ensure there is no border on the island of Ireland as the Republic of Ireland remains in the EU.
Northern Ireland Protocol
The protocol stipulates that Northern Ireland will de facto continue to follow the rules of the EU's customs union and single market after the end of the post-Brexit transition phase on December 31.
A form does not have to be filled out when a letter, postcard or document is sent to an EU country, the Post Office said.
According to the Post Office, 45% of international parcels posted in Britain are destined for the EU.