Britain's departure from the EU was set in law Wednesday as London returned a signed treaty and MEPs prepared to vote to ratify the divorce.
After half-of-century of sometimes awkward membership, the UK will leave the EU at midnight Brussels time on Friday.
The day began with Britain's permanent representative – soon to be ambassador to the EU Tim Barrow handing back the withdrawal agreement.
This had already been signed by Brussels' top figures and had been sent to London for Prime Minister Boris Johnson to sign for the UK government.
"This step ensures that the UK has fulfilled its legal obligations regarding our exit from the EU," his office said.
Then Nigel Farage, leader of Britain's Brexit Party and for two decades a thorn in Brussels' side in the European Parliament, spoke.
"At 11pm UK time on January 31 will leave the European Union and we pass the point of no return," he declared.
Mr Farage said he had loved playing the "pantomime villain" in the Strasbourg assembly, feeding opposition to Europe at home with theatrical YouTube clips.
But he insisted on the seriousness of Brexit, comparing its significance to Henry VIII taking Britain out of the Catholic church in 1534.
"He took us out of the Church of Rome, and we are leaving the Treaty of Rome," he said, referring to the EU's 1957 founding document.
Later in the day, Mr Farage's colleagues in the European Parliament were to gather for a historic vote to incorporate the withdrawal agreement into EU law.
This will be the last legislative act of the 73 remaining British MEPs, and will be followed by a ceremony of farewell.
After Brexit the United Kingdom will become what the EU calls a "third country," outside the union, but the political and economic drama is likely to continue.
Britain and Europe will continue to apply EU rules on trade and free movement of citizens until the end of the year while negotiating a free trade agreement.
In the face of scepticism in EU capitals, Mr Johnson insists he is optimistic that a comprehensive free trade deal can be reached before the next cliff-edge.
But negotiations will be tough between Britain, the world's sixth biggest economy, and the EU, a 27-nation single market with a population of 450 million.
Fishing rights, residency and working rights for citizens, tariff free trade, and access to Europe for Britain's huge services sector will all be on the table.
"Brexit is a loss for us all," European Commission Vice President Maros Sefcovic said on Tuesday.
He said it was important for the EU "to maintain our unity" as Europe negotiates the future partnership with the UK.
The British minister for Europe attending the meeting, Christopher Pincher, expressed optimism on what the talks would yield.
"We're looking forward to a very different world and a very different relationship," he told reporters on Tuesday.
Mr Farage will leave Brussels on Wednesday, but the other Brexit Party MEPs, will march out of the parliament on Friday morning with the Union Jack in hand.
They will join their leader in London at a Brexit party, before the houses of parliament.
EU chief Brexit negotiator Michel Barnier on Monday warned "it is absolutely clear that there will be negative consequences" from Brexit.
"Whatever agreement we reach on our future relationship, Brexit will always be a matter of damage limitation," he said in Belfast.