A diminished BBC would weaken the country as a whole, the corporation’s chairman will warn in a speech later.
Sir David Clementi will say putting the broadcaster’s services behind a paywall would lessen its ability to “bring the country together”.
Not everybody would be able to access the “live important moments we enjoy as a nation”, like Royal weddings and Olympic successes, he will tell staff.
His comments come amid a debate about the future of the licence fee.
In December, Prime Minister Boris Johnson said the licence fee needs “looking at”, and Culture Secretary Nicky Morgan last week launched a public consultation on whether non-payment of the TV licence fee should remain a criminal offence.
Some have suggested a Netflix-style paid subscription service as an alternative.
In his speech in Salford, Sir David will say: “The BBC is a great national asset; a diminished BBC is a weakened United Kingdom.
“Sitting behind a paywall, it would no longer be the place that brings the country together for the Strictly final, or Gavin & Stacey on Christmas Day, or the Armistice Anniversary or Holocaust Memorial.
“Nor would it be the place that all could turn to celebrate live important moments we enjoy as a nation: Royal Weddings or Jubilees, or Olympic successes.”
Sir David will warn “it would be very unlikely to continue the level of properly curated programmes for children, or indeed the brilliant Bitesize education services”.
And the BBC “would not have the same commitment to investing in home-grown ideas and talent”.
It was revealed last month that 450 jobs will be cut from BBC News under plans to complete its £80m savings target by 2022.
Sir David’s speech will note how the government would have to take over the £250m investment that the licence fee contributes to the World Service.
“The BBC will engage fully with the government’s [licence fee] consultation, but it must be based on the evidence,” advance comments from his speech said.
“A decision of this scale, taking hundreds of millions out of the BBC and the creative economy, must not be taken in isolation.”