The operator of the King's Theatre in Edinburgh said the move would result in "the massive loss of £2.3 million at the worst possible time for the theatres".
Qdos had been planning to stage 34 pantos across the UK this Christmas with some of the nation's biggest stars including John Barrowman and Craig Revel Horwood.
It is discussing the fates of the other 30 with those venues - "a complex process" that it says will take several weeks.
Qdos set a deadline of Monday August 3 to get "clarity" from the government about the reopening of theatres.
But last week, Culture Secretary Oliver Dowden told BBC Radio 4 he didn't expect to be able to give a date for allowing audiences in without social distancing until November "at the earliest".
Pantomimes are crucial to theatre earnings, but are unlikely to be financially viable with social distancing restrictions in place.
On Wednesday, Qdos confirmed that four shows had been rescheduled:
Cinderella at the Mayflower in Southampton, due to star Craig Revel Horwood and Debbie McGee, was due to run from December 11 to January 3, but has been put back to Christmas 2021.
Beauty and the Beast at His Majesty's Theatre in Aberdeen, scheduled to run from November 28 to January 3 2021, will now run from December 4 2021 to January 9 2022.
Sleeping Beauty at the King's Theatre in Edinburgh, scheduled to run from November 28 to 17 January 2021, will now run from November 27 2021 to January16 2022.
Goldilocks and the Three Bears at the Grand Opera House in Belfast, scheduled to run from November 28 to January 10 2021, will now open in "late 2021".
In a statement, Capital Theatres, which runs the King's Theatre in Edinburgh, said the seasonal show accounted for 30 per cent of the company's annual income.
Chief executive Fiona Gibson said the cancellation was the "biggest blow" to face the company since the coronavirus lockdown was imposed in March.
"Capital Theatres is Scotland's largest theatre charity and the impact of this decision is devastating," she said.
So far the Bridlington Spa is the only theatre on the East Coast to confirm its pantomime will go ahead. The Adventures of Peter Pan will run from December 19 to January 3.