Boris Johnson has told pupils singing Rule, Britannia! is politically acceptable amid debate over the song’s historical meaning.
The PM defended the song after the BBC said it would play a version at the Last Night Of The Proms without the words.
The BBC has since said the decision to drop the lyrics at the event next month was prompted by COVID-19 restrictions.
There had been reports the song would be dropped altogether, along with Land Of Hope And Glory, because of their perceived association with colonialism and slavery.
Johnson made the comment during a visit to Castle Rock School in Coalville, Leicestershire, as pupils returned for the first time since the coronavirus lockdown was implemented.
In a speech to pupils, Johnson cited the debate around Rule, Britannia! as an example of something teachers are able to help pupils understand as a result of being back in classrooms.
He said: “Is it politically acceptable to sing Rule, Britannia!? Yes.
“When you’re struggling with complex questions or something that you’re worried about, somebody, very probably a teacher, a brilliant teacher, will say something and a light will go on, the clouds will lift and you will never, ever forget that moment.”
The lyrics of Rule, Britannia! are based on a poem by James Thomson. It was set to music by Thomas Arne in 1740.
Its lyrics include: “Rule, Britannia! Britannia, rule the waves! / Britons never, never, never will be slaves.”
"The nations, not so blest as thee / Must, in their turns, to tyrants fall.”
"While thou shalt flourish great and free / The dread and envy of them all.”
When asked on the matter, Number 10 spokesman previously said Johnson believes in tackling the “substance” not the “symbols” of problems.
“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.”