By Daniel J. McLaughlin
There are many traditions to Last Night at the Proms, including the customary waving of the flags.
In recent years, EU flags have joined the Union Jack and other international flags in the audience, as a protest against Brexit.
After the blue flag with yellow stars was waved proudly by audience members at this year's concert, some have accused Remainers of "hijacking" Last Night at the Proms.
However, protesters have defended the flags, saying they were showing solidarity to international musicians.
According to the Express, viewers were left "disgusted" and complained bitterly after the show was "hijacked by anti-Brexit campaigners spreading pro-EU propaganda".
They report: "Before the event Remainers handed out 50,000 EU flags across the various Last Night of the Proms events.
"Since the 2016 EU referendum, bitter Remain campaigners have been allowed to hijack the music festival by waving EU flags instead of the traditional Union flag to show their unity with Brussels."
Some viewers took to social media to vent their frustrations, accusing Remainers of hijacking a British institution and showing "the usual dollop of BBC cultural obsessions like Remain and Pride".
One viewer wrote: "Just watched it now – full of EU flags and hats. I really want to know what motivates these EU fanatics. They must hate their country."
Jonathan, a man who handed out EU flags at Last Night at the Proms, defended "politicising" the classical music event on LBC.
He called in to Nick Ferrari's show to "bust some myths" about the Brexit protest.
The caller said: "Nick, it's not a question of political. Last Night at the Proms is a great international celebration, and people wanted to show their allegiances to many countries, but also to the EU.
"There's nothing wrong with having multiple allegiances."
Jonathan said he was "proud" to have handed out EU flags to everyone who wanted to show support to musicians from across the world.
He mentioned that the bloc - with its freedom of movement and copyright laws - is important for musicians.
After Ferrari asked how much he was charging for the flags, the caller said that they were "absolutely free".
He explained: "They were free and the idea that was the Commission who were funding it, or it was out of Jean-Claude Juncker's personal bank account is absolute nonsense."
He added that a gentleman was charging £3 for Union Jack flags.
Last Night at the Proms was Prom 75 of the eight-week summer season of classical music, held mainly in the Royal Albert Hall in London. There were also performances in Belfast, Glasgow, Swansea, and London's Hyde Park.
The Proms is the world's largest classical music festival, and it was founded in 1895.
At this year's Proms, organised by the BBC, there were 85 concerts involving 191 conductors and 83 orchestras, choirs and ensembles over 58 days.
There are many traditions for the Last Night at the Proms, including the customary waving of the flags, and a second half made up of British patriotic songs.
Edward Elgar's Pomp & Circumstance March No. 1, which includes Land of Hope and Glory, Sir Henry Wood's Fantasia on British Sea Songs, and Rule, Britannia! are traditionally played. The concert concludes with Jerusalem and the British national anthem, God Save the Queen.
Auld Lang Syne and an arrangement by Benjamin Britten have also been played.
You can watch Last Night of the Proms here.