The diction of most younger actors is so poor and the acoustics in most theatres in Britain so bad that audiences are struggling to understand what is being said on stage, some of Britain’s leading theatrical personalities said yesterday.

The director Sir Peter Hall, who founded the Royal Shakespeare Company and headed the National Theatre, told The Times that “most actors under the age of 40 are struggling to be heard”. He was backed by the actor Edward Fox who ridiculed younger actors for mumbling their lines in the pursuit of realism. Both blamed the decline in diction on the demise of repertory theatre and young actors doing more work on television and commercials than on stage.

Sir Peter said that he gets more complaints from audiences about this issue than any other. “It is the most regular complaint,” he said. “Most theatre directors will tell you the same. Actors now think that if they raise their voice, they are being ‘unrealistic’. I tell them: ‘What you do is unreal. You’re wearing someone’s else’s clothes and speaking someone else’s words’.”

Fox, a star of stage and screen who is best known for The Day of the Jackal, said that actors mistakenly thought being quiet made them more realistic. “They think they’re being clever,” he said. “Someone should disabuse them of that fact. Audiences want to hear what they’re saying.”

He recalled how actresses such as Dame Peggy Ashcroft and Dame Edith Evans had always believed that acting was about communicating the words they had been asked to learn and that the control of breathing and diction was everything. During his early days, a young actor who appeared at an audition without those skills would hear a voice from the stalls saying: “Thanks very much, goodbye.” The problem was now so acute that television sound-recordists had told him that the young actors “won’t even be picked up if the microphone is next to their cheek”.

The two were speaking to The Times before the opening of new playhouses with which they have been closely involved respectively — the Rose, which opened yesterday in Kingston upon Thames, and the Royal Hall in Harrogate, which the Prince of Wales will open today. Their criticisms were welcomed by other actors. Sir Tom Courtenay, one of Britain’s most respected actors, said that he too often struggled to hear lines being delivered.

He joked about how handsome young actors are being cast and somehow assuming that it is “just enough that I come on and be lovely”. He said of his own performances: “I may be bad, but at least they can hear me.”

Malcolm Sinclair, the Olivier-nominated actor, said that drama schools were not doing enough to teach actors the basics: “The whole ‘method thing’ came crashing in and the technical craft side has got neglected.”

Sir Arnold Wesker, considered one of the key figures in 20th-century British drama, said: “It’s about time someone came out and said this. The mumbling has got so bad that they even mumble on television and in the cinema. I don’t know why they do it. They’re pretending that it’s real life, but theatre is not real life.”

Stephen Unwin, the Rose’s new artistic associate, said that, as director of the English Touring Theatre, he performed in theatres across the country. He said that the acoustics of 60 per cent of them were awful. “Everybody who’s been into the Rose says that they [the acoustics] are better than the Cottesloe [National Theatre] or the Swan [RSC Stratford].”

The Royal Hall in Harrogate — where Sir Edward Elgar conducted, Dame Nellie Melba sang and Dame Margot Fonteyn danced — is one of the finest creations of Frank Matcham, regarded worldwide as the greatest of theatre architects. Its concrete was crumbling so badly that it was closed for safety reasons in 2000 — only to be saved by a local enthusiast, Lilian Mina, who fought off a proposal to turn the site into a car park.

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