Protests about the closure have gathered pace since last May's announcement that the 240–year-old theatre would close for emergency refurbishment.

As a result of the closure, Kenneth Branagh's production of Ivanov was one of the canceled productions. Following the announcement the theatre's artistic director, Simon Reade, resigned.

Plans to let out the premises to weddings and conferences after the venue reopens have only added to fears that the theatre — which cultivated the careers of Peter O'Toole and Daniel Day Lewis — was, as the letter puts it, "in danger of being allowed to fade away."

According to the theatre's chairman Rupert Rhymes, the £7 million refurbishment is necessary on health and safety grounds. The 650-seat venue was, said Rhymes, financially failing with some shows only operating at 30 percent capacity.

There are no plans for the company to tour or stage shows at a temporary base during the refurbishment. The letter's signatories number over 120. Also included are Eileen Atkins, Sir Ian McKellen, Richard Griffiths and Emma Thompson. "Most of us have appeared with the company," it said. "We call for the immediate appointment of an artistic team, in particular an artistic director, so a programme of work can be planned for the period of closure."