The Old Vic, which opened in 1766, is a pillar of Britain’s theatrical community and has nurtured the careers of generations of great actors including Peter O’Toole and Daniel Day-Lewis.

The signatories to the letter are protesting the theatre’s decision to stop productions for 18 months for refurbishment. They include Dench, Maggie Smith and Thompson — who have five Oscars between them — as well as Alan Rickman and Ian McKellen.

In the letter they said that the stoppage, together with plans to rent out the refurbished building for conferences and weddings, would kill off the resident Old Vic Theatre Company.

“What is clear is that the Bristol Old Vic Company is in danger of being allowed to fade away,” they wrote.

So far, there are no plans for the theatre company to go on tour, or set up a temporary base while the theatre itself undergoes its $14 million refurbishment.

Theatre officials say the repairs are necessary to update what they describe as a hazardous venue to one that is state-of-the-art. They note that audience figures have been falling recently — something a facelift theatre may help reverse.

But Rickman, who recently appeared in the blockbuster film “Harry Potter and the Order of the Phoenix” asked: “Would somebody please explain why I am receiving letters asking for money to preserve the fabric of a building which appears to have nothing happening in it?”