Prime Minister Boris Johnson called for an end to "cringing embarrassment about our history" after the BBC decided to strip lyrics from traditional Last Night of the Proms favourites such as Land Of Hope And Glory.
The broadcaster revealed details of its schedule for the Last Night event after reports that anthems Rule Britannia! and Land Of Hope And Glory could face the axe over their perceived association with colonialism and slavery.
On Monday night, the BBC issued a statement saying the two songs would be performed by the orchestra, but without singing during the September 12 concert.
Mr Johnson shared his reaction during a visit to Devon on Tuesday, telling reporters: "I was gonna tweet about this, but I just want to say... if it is correct, which I cannot believe that it really is, but if it is correct, that the BBC is saying that they will not sing the words of Land Of Hope And Glory or Rule Britannia! as they traditionally do at the end of The Last Night of The Proms.
"I think it's time we stopped our cringing embarrassment about our history, about our traditions, and about our culture, and we stopped this general fight of self-recrimination and wetness.
"I wanted to get that off my chest."
The BBC said there had been "unjustified personal attacks" on social media on Finnish conductor Dalia Stasevska, who will be at the helm of the Last Night this year.
"Decisions about the Proms are made by the BBC, in consultation with all artists involved," it said.
There will be no live audience to sing along and wave flags because of coronavirus restrictions.
The national anthem will still be sung during the event, which will air on BBC Radio 3 and on BBC One and feature soprano Golda Schultz and the BBC Symphony Orchestra at the Royal Albert Hall in London. A new arrangement of Jerusalem will also be included.
The BBC said: "The Proms will reinvent the Last Night in this extraordinary year so that it respects the traditions and spirit of the event whilst adapting to very different circumstances at this moment in time.
"With much reduced musical forces and no live audience, the Proms will curate a concert that includes familiar, patriotic elements such as Jerusalem and the national anthem, and bring in new moments capturing the mood of this unique time, including You'll Never Walk Alone, presenting a poignant and inclusive event for 2020.
"The programme will include a new arrangement by Errollyn Wallen of Hubert Parry's Jerusalem alongside new orchestral versions of Pomp And Circumstance March No 1 Land Of Hope And Glory' (arr Anne Dudley) and Rule Britannia! as part of the Sea Songs, as Henry Wood did in 1905."
Earlier, a Number 10 spokesman said Mr Johnson believes in tackling the "substance" not the "symbols" of problems, after the Sunday Times reported that the songs could face the axe.
"This is a decision and a matter for the organisers of the Proms and the BBC," the spokesman said.
"But the PM previously has set out his position on like issues and has been clear that, while he understands the strong emotions involved in these discussions, we need to tackle the substance of problems, not the symbols."
Culture Secretary Oliver Dowden tweeted: "Rule Britannia! and Land of Hope and Glory are highlights of the Last Night of the Proms.
"(I) Share concerns of many about their potential removal and have raised this with (the) BBC.
"Confident forward-looking nations don't erase their history, they add to it."
Business secretary Alok Sharma suggested the BBC use subtitles so viewers can sing along at home.
He told Times Radio: "We've heard the BBC's position that they will maintain the traditions. Personally, I would like to see the lyrics sung and of course it is always possible to put lyrics up as subtitles on the screen so if people want to they can join in at home."
The former chairman of the Equalities and Human Rights Commission, Trevor Phillips, told the station that the BBC panicked when it came to issues of race.
"The real problem the corporation has is that it is always in a panic about race, and one of the reasons it is always in a panic is that it has no confidence.
"The principle reason it has no confidence... is that there is no ethnic diversity at the top of its decision-making tree," he said.
"What you have is rooms full of white men panicking that someone is going to think they are racist."
But TV choirmaster Gareth Malone suggested Rule Britannia! was outdated, tweeting: It's time for Rule Britannia! to go."
Rule Britannia! – strongly associated with the Royal Navy – is deemed problematic by some because of Britain's role in the slave trade.
It has lyrics such as Britons "never shall be slaves" and that "while thou shalt flourish great and free, the dread and envy of them all".
Land Of Hope And Glory features the music of Edward Elgar and the lyrics of Arthur Benson and has lyrics such as "Thine Empire shall be strong" and "God, who made thee mighty, make thee mightier yet."