As grey afternoon slipped into dusk, the EU flag was taken down from the UK’s permanent representation to the EU in Brussels. At the end of the working day on Friday 31 January, a small crowd watched in silence as an official at a narrow window reeled in two flags, before restoring the British one.

For years the blue and gold-starred flag flew alongside the union jack at the “perm rep”, the nerve centre of British EU diplomacy for nearly half a century. Now, as the UK seeks a new place in the world, the union jack flies alone.

For the EU this is nothing to celebrate. “We are all very, very sad that the UK will leave us on Friday, but we now have to make the best out of the situation,” said David McAllister, a German MEP with Scottish roots.

'The irony is we got things right by 2015': UK's Brussels envoys on Brexit Read more

By midnight Brussels time (11pm GMT), the UK’s 47-year stay in the European club of nations will be history. British ministers will no longer play any part in agreeing EU laws and decisions. British diplomats will be denied routine access to EU buildings. And the UK’s 73 members of the European parliament and two judges at the European court of justice are out of a job.

British flags in the EU council of ministers will be quietly taken down after office hours (although officials have relented on a previous ban on cameras). The flags will be stored in a cupboard along with those of other “third countries” – nations foreign to the EU.

In the final hours of parting, European leaders sought to put a brave face on the loss of a big member state that brought economic and diplomatic heft to the club. “We know very well that as the sun rises tomorrow, a new chapter for our union of 27 will start,” said the president of the European commission, Ursula von der Leyen.

She said Europe had a “once-in-a-generation opportunity” to lead the way in confronting the climate emergency and the challenges of digitalisation. “Our experience has taught us that strength does not lie in splendid isolation, but in our unique union.”

Facebook Twitter Pinterest Ursula von der Leyen speaks in Brussels alongside Charles Michel (left) and David Sassoli. Photograph: John Thys/AFP via Getty Images

She was speaking alongside two other EU presidents, Charles Michel of the European council and David Sassoli of the European parliament, in the map room of the Parlamentarium, the parliament’s state-of-the-art visitor centre.

To reach the map room, visitors pass a long corridor decorated with black-and-white images recounting moments in Europe’s modern history, including the 1974 Eurovision song contest in Brighton and a scene from the miners’ strike in 1985. Downstairs is a miniature European parliament debating chamber, with tiny wooden figures depicting MEPs. The British pieces will soon be plucked off the board.

This week British MEPs bade an emotional goodbye to the chamber, singing Auld Lang Syne after the parliament voted to approve the Brexit withdrawal agreement. The MEPs had not even left the building when the treaty was sent to the EU’s 27 ambassadors for the final seal of approval. By Thursday lunchtime, 27 “yes” emails had landed in the EU council’s inbox. The divorce was complete, not with a flourish but a dry written procedure.

The treaty and blue leather-bound “instruments of ratification” – the British parliament’s assent, hand-delivered by the UK’s EU ambassador this week – will be filed in the council archives in Brussels for 30 years.

Brexit party MEPs were jubilant. “Today we celebrate the beginning our independence,” Ann Widdecombe told a thicket of camera crews on the steps of the European parliament on Friday morning.

Led by a piper in Highland dress, the party’s MEPs whooped and cheered as they wheeled their suitcases over the vast esplanade in front of the parliament into the cobbled Place du Luxembourg. A couple punched the air, shouting “Brexit”, while others posed with Brexit party turquoise umbrellas.

Facebook Twitter Pinterest A piper leads Brexit party MEPs out of the European parliament in Brussels. Photograph: Thierry Monasse/Getty Images

The piper, Ben Buckland, a Brexit supporter who described the European parliament as “Satan”, played Widdecombe’s taxi out of the square, an enormous union jack flying out of its window.

The previous night very different emotions were on display as remain supporters danced to Scottish folk music. “A ceilidh is such a great way of bringing people together,” said the Green MEP Ellie Chowns, who had organised the event. “We are drowning our sorrow in music and dance.”

‘Just gutted’: Eurostar passengers in Paris reflect on Brexit day Read more

British residents in Brussels crammed into the gothic splendour of the town hall at the invitation of the city’s mayor, Philippe Close. “Whatever happens, the thousands of Britons who remain in Brussels remain Bruxellois [Brussels residents],” he told them. Speaking alongside the UK’s bilateral ambassador to Belgium, Close added that a wise man would say nothing about Brexit. The crowd laughed.

Outside on the Grand Place, Brussels’ magnificent central square was lit up in union jack colours. A band playing covers of David Bowie and John Lennon alternated with the EU anthem, Ode to Joy, on the bagpipes. But as the light rain went on and off, the numbers were never high. “It is a bit flat here, it is a non-celebration,” said Deirdre Thomas, a retired teacher who has lived in Belgium for 25 years. “It is just something that has happened that the British have to get on with.”

Even the Brussels transport authority, STIB-MIVB, offered a tribute to the British – a video clip that highlighted many British-related stops on the tram and metro network, including Churchill, Darwin, Liverpool, Lancaster and “Engeland”. As the lilting melancholy music faded, the penultimate frame concluded: “Mind the gap when leaving.”