Pantomime season "won't happen" over Christmas because of the financial impact of the coronavirus pandemic, according to theatre director Sir Nicholas Hytner.
Sir Nicholas said the entire arts sector is "on the brink of ruin" because even the one-metre social distancing rule would not be enough to keep the industry financially stable.
Speaking on the Andrew Marr Show, he also said the industry needs "unprecedented and immediate" investment which would enable performers to find a way to work.
Asked if changing the two-metre rule would be enough, he said: "Even with the one-metre social distance, the maximum capacity any of us would be able to manage even if we had a go would be around about 25%-30%, which simply isn't enough to run a big show or an opera or a ballet.
"Most of that won't be able to happen until the other side of social distancing and, honestly, the entire arts sector is on the brink of ruin and that's not just the theatres."
His comments came after research by the Society of London Theatre and UK Theatre suggested 70% of theatres will run out of money by the end of 2020.
Sir Nicholas also said this would put the Christmas pantomime season in jeopardy, causing a further loss in income.
He added: "This is the time of year when theatres have to start spending on their Christmas shows, it has to start now, and nobody can do that at the moment because there's been no box office for the last three months, so there's no cash.
"At the moment, panto season won't happen, whatever happens to the pandemic between now and Christmas and panto season is when entire families go to the theatre and when theatres make the money at the box office that sustains them through the rest of the year."
Earlier this week, Phoebe Waller-Bridge, James McAvoy and Toby Jones backed a letter warning that the UK theatre industry stands "on the brink of ruin".
The letter stated: "Without Government investment, theatres will be forced to close and may never return.
"The threat of British theatre being destroyed by accident is as real as it is bleak.
"It would not only be a spiritual tragedy but an economic one."
Actress Dame Kristin Scott Thomas said: "The performing arts, theatre, dance, opera, music, all these things are really the heart of our culture and it's so internationally admired.
"People come from all over the world to come to the theatre in London, you go into any theatre foyer in the West End and you'll hear a multitude of other languages."