Council President Charles Michel and Commission President Ursula Von der Leyen undertook a signing ceremony this morning in Brussels.
It comes as MPs are set to debate the new trade deal in the House of Commons this afternoon.
In a statement on Twitter, EU chief negotiator Michel Barnier said: “As the new agreement is signed, I want to thank all teams in the EU Commission, UK Task Force, Council & European Parliament.”
“Each person played their part in building European unity. Thank you.”
The Prime Minister’s official spokesman said the international treaty would be sign flown across the Channel.
An RAF plane will transport the treaty, accompanied by UK and EU officials, and the document is expected to be signed by the Prime Minister in Downing Street on Wednesday afternoon.
Reacting to the EU signing, a UK Government source told Express.co.uk: “This is a historic day for Britain.”
The occasion comes after the EU governments approved the deal on Tuesday paving the way for its provisional application from Jan 1st allowing the deal to be introduced.
The deal preserves Britain’s zero-tariff and zero-quota access to the EU’s single market of 450 million consumers, was reached on Dec 24th four and a half years after Britons voted by a slim margin in a referendum to leave the bloc.
German Foreign Minister Heiko Maas said: “I am pleased that all EU 27 have given approval. By joining forces, we have succeeded in preventing a chaotic turn of the year.”
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