LONDON - In the hours before the United Kingdom's formal departure from the European Union, hundreds of politically-minded Britons flocked to the streets and public spaces of London's Westminster district, the centuries-old home of the country's legislature.
It has been an often contentious and occasionally fraught three-and-a-half years since a slim majority of voters opted for a future outside the world's largest political bloc. And on a night when that nation-altering 2016 referendum vote would become a reality, there were far more supporters of Brexit out in public than there were opponents.
Dozens of national flags in the U.K.'s familiar red, white and blue pattern provided splashes of color across Parliament Square on an otherwise grey wintry evening; some flapping from the permanent mast poles around the perimeter, others draped around the necks of Brexit's most ardent supporters.
"It's a very big celebration for me personally," said Michael Kinane, a Brexit supporter from Essex, just east of London, who sported a baseball cap decorated with the British flag. "I've always believed in coming out and being independent from the EU."
It has been almost half a century since the United Kingdom signed up to join other major European nations in a precursor to the EU, and the decision to begin unpicking the political, legal and constitutional threads that have bound this island nation to the European continent for so many years has proved painful for many on both sides of the English Channel.
Boris Johnson, the prime minister who effectively surfed to power on a wave of populist resentment about British membership of the EU, broadcast a message late Friday calling the formal act of separation "an astonishing moment of hope."
He acknowledged that there would be those who felt "a sense of anxiety and loss," but insisted that Britain's exit from Europe was "not an end but a beginning."
In one sense this precise moment of parting occurs only on paper, since the U.K. will continue to abide by the EU's rules and regulations for the next 11 months during an implementation period agreed with the EU to give businesses and citizens time to adjust to as-yet uncertain new circumstances.
Johnson and his political allies in the Conservative Party, still buoyed by their decisive electoral victory last month, have promised that the U.K. will agree a wide-ranging new trading relationship with the EU, by far its largest destination for both goods and services.
But senior politicians in Brussels have repeatedly warned that Johnson's negotiating timeline is highly ambitious, and their insistence on that point has meant concerns about an economically damaging "hard Brexit" at the end of the implementation period still persist.
Office workers on Whitehall, the street that hosts several government departments, came out to witness the start of the pro-Brexit street party Friday evening. Two young professionals watched the marching and chanting as their colleagues several floors above them peered out from a window.
"Only a small crowd, but it looks a bit of a spoof," said one, who gave his name only as Joe. "I really don't know what to make of it."
His colleague, Megan, said the flag waving masked what really lay ahead for Great Britain as it charted a new, independent course for itself on the international stage, with all the argument-provoking possibilities and pitfalls that formed the core of a dispute, which had marred the country's political discourse for the past couple of years.
"I think the opportunities are going to come, after many businesses go bust in the weeks and months that follow the real exit, which will be on the first of January 2021," she said above the noise.
"They're trying to move us away from EU-centric language to cover up the fact that when it comes to the real day one, there is going to be problems, big problems and we're not ready."
The three most senior leaders of the EU's institutions published an opinion piece in several European newspapers Friday morning, including the London Times, with a focus on the new relationship between the two sides and the challenges that lie ahead.
"We will have to work hard to weave together a new way forward as allies, partners and friends," wrote European Commission President Ursula von der Leyen, European Council President Charles Michel and the head of the European Parliament, David Sassoli. "How close that partnership will be depends on decisions that are still to be taken."
"That work continues as soon as the sun rises tomorrow," they concluded, describing Brexit as a "new dawn for Europe."