The EU and UK have just reached a post-Brexit trade agreement after 10 months of negotiations to reduce the economic consequences of Britain's about to leave the bloc.

"The deal is complete," British Prime Minister Boris Johnson tweeted today, while European Commission President Ursula von der Leyen also confirmed "an agreement was reached".

"It's a long and winding road, but in the end we reached an agreement. The single European market will be fair and still be," she said.

Prime Minister Johnson later said at a press conference that Britain's post-Brexit trade deal with the European Union (EU) provided "new stability and certainty".

"We will be friends, allies, supporters of the EU and really never forget the EU is the number one market," he said.

The UK officially left the EU in January after a deeply divided referendum in 2016. It was the first country to leave the political and economic bloc formed when the continent was rebuilt after World War II.

London remained bound by EU rules during the midnight transition period on December 31, when Britain exited the bloc's single market and customs union.

The European Commission will send the written agreement to the EU member states.

The UK parliament will also have to suspend the year-end holidays to vote on the deal before December 31 ends.

German Chancellor Angela Merkel said she "believes" the Brexit deal signed between the EU and UK is a "good result", saying that the bloc and the UK agreeing on a future relationship "has" significance.

"Even outside the EU, the UK will remain an important partner for Germany and the EU", Ms. Merkel said, while French President Emmanuel Macron said that "EU unity and solidarity has been paid off.