Actors aren't the only ones to blame for mumbling, says writer Andrew Davies

It has become the bane of a television viewer's life: the mumbling actor who swallows his lines leaving them reaching for the subtitles button.

But the widespread sound problems on modern television should not be blamed just on its hapless stars, the writer Andrew Davies has said, as he warns directors must take their fair share of the blame.

Davies, who has adapted some of Britain's most acclaimed period dramas including Pride and Prejudice and War and Peace, said drama directors often fail to notice when actors are mumbling because they already know the lines so well. As such, he said, they assume the words are being said clearly, leaving the problem unnoticed until it reaches the screen.

Speaking about his work adapting classic novels at the Emirates Airline Festival of Literature in Dubai, he admitted directors "get sick of me" constantly reminding them to make dialogue audible and scenes well-lit.

The topic of mumbling has become increasingly central to British television, after a series of on-screen disasters beginning in earnest in 2012 with Birdsong and continuing to current BBC series SS-GB.

In 2014, Jamaica Inn received more than 2,000 official complaints after viewers lamented its dark setting and inaudible Cornish lines.

Sound quality problems have also previously been blamed on modern televisions, which have speakers at the back, and actors choosing not to enunciate.

When asked whether he had any insights into why mumbling appeared to be such a problem, Davies said: "I don't think it's usually a problem with the dialogue.

"It can be a problem with flatscreen televisions tend to have not very clear sound.

"But I also think yes, actors who are trying to make it sound more like natural speech sometimes do tend to mumble. "And directors know the lines so well that they can hear them and they think they're being said clearly.

"I watch the rushes and I'm full of complaints. Directors get sick of me saying 'I can't see, it's too dark, and I can't hear what they're saying because it's not clear'.

"I think this can happen."

He added: "Another problem of course is that a lot of people who complain are quite hard of hearing.

"My wife and I both tend to watch dramas with the subtitles on."

Davies' own dramas have not been the subject of any major complaints, though some viewers used social media to note they had struggled with parts of War and Peace last year.

He is currently working on a new adaptation of Les Miserables for the BBC, which he warned is likely to upset fans of the musical after he chose to go straight back to the Victor Hugo novel.

"I think it's a wonderful book," he told an audience.

"I don't think anybody has adapted it right yet.

"In a way, people who love the musical are going to be so angry and 'who does he think he is' with this. But I'm trying to rescue it from that awful musical.

"I know a lot of people who adore the musical who, if they watch my adaptation, are going to say 'where are the songs? He left the best bits out!'"

He has now written the first draft and is awaiting feedback from the series' producers.

Next, he said, he hopes to adapt Dickens' Dombey and Son and Vikram Seth's A Suitable Boy, joking it would "give him a reason to stay alive" at the age of 80.

He has also written a drama about the foundation of the NHS and Nye Bevan, confirming it had not been made by the BBC.

He claimed the decision was down in part to a concern about being seen to be too left wing.