Simon Rattle, music director of the London Symphony Orchestra, considers it "a miracle" they are headed to France for their first international shows since the pandemic, though Brexit still poses a long-term threat.
The logistics of moving nearly 100 musicians and all their instruments for a four-week residency at the Aix-en-Provence Festival in southern France were tricky at the best of times.
In the middle of a pandemic, with ever-changing rules on foreign travel and quarantines, they became fiendishly complex.
"I think the Aix festival, who have been one of the boldest and bravest of any of the summer festivals, was tearing out what remained of their hair in the last weeks," Rattle told AFP.
He was speaking ahead of the London Symphony Orchestra (LSO)'s departure for the festival, which runs from June 30 to July 25.
It took a flurry of diplomatic activity that went right up to the culture ministries in both countries, for a deal to be struck.
Since most were vaccinated, the orchestra was granted permission to travel between their hotel and the venue for rehearsals during their quarantine.
"It's very symbolic that we were able to make this happen," said LSO managing director Kathryn McDowell, adding that the orchestra had been crossing the Channel since 1906.
But even if the immediate challenges have been overcome, the problems of Brexit and the near-total lack of government support for musicians in Britain have only just begun.
"This is a complicated time, you know, in a country which does not support culture financially in the way that most of Europe does," Rattle said.
- 'Looming catastrophe' -
The LSO has been a regular visitor over the past decade to the Aix festival, one of the world's leading opera and classical music events alongside Salzburg and Beirut.
But its days of travelling regularly around the continent may be numbered.
Since Britain's exit from the European Union, its musicians are no longer guaranteed visa-free travel to the EU, triggering heavy costs and an administrative burden for touring.
Orchestras face the additional difficulties of transporting equipment in heavy-duty lorries, which are now permitted just three stops in the EU.
Singer Elton John is among many warning of a "looming catastrophe" for British musicians if they lose the chance to tour abroad.
For now, the LSO, which had been booked for last year's cancelled Aix Festival, is excited to be back on the road.
It will play not one, but two, operas: a modern creation, "Innocence", and a classic from Wagner.
"It's a complete miracle," said Rattle. "Playing an opera like Tristan und Isolde is almost beyond pipe dreams."
- 'Insane in every way' -
But Brexit will likely push the LSO to review its financial model, since it relied on European shows for 40 percent of its income before the pandemic.
That said, environmental concerns may have forced a change in any case.
"Last year... we should have been on tour 99 days out of the year, which is, of course, insane in every possible way, both for the planet and for people's energy and sanity," Rattle told AFP.
"But it was the only way that an orchestra like this can survive."
A big part of the problem, he said, is the lack of government support for musicians in Britain.
The LSO's members are not on a salary -- they are paid when they play.
"Most of the European orchestras, almost without exception, have a salary, and they have been able to live," said Rattle.
"We have had to become pirates, in the best possible way."
He said the LSO would now have to "make up a whole new financial way of living in which playing in Europe is not the main part of our support".
That is hard to swallow for such an international orchestra, made up of 26 nationalities.
Brexit "is a story of unintended consequences. Nobody has thought very much about the effect on the cultural sector in England," Rattle said.
"But of course, nobody wants it to be a disaster."