First, it was the BBC’s costume drama Jamaica Inn, which attracted thousands of complaints in 2014, then last year’s Happy Valley. Now, the alternative history miniseries SS-GB has become the latest primetime BBC programme to draw criticism about characters mumbling their lines.

Following the success of TV shows such as Amazon’s The Man in the High Castle, the BBC hopes its five-part dramatisation of Len Deighton’s 1978 novel, which imagines that Germany won the Battle of Britain and the Nazis occupy the south of England, will be a hit.

But the first episode of SS-GB – which had already faced some scathing reviews from TV critics for its first episode on Sunday night – has been criticised by viewers who said they had struggled to hear what was going on.

The broadcaster has promised to promised to examine the sound levels before the next episode is broadcast after dozens of viewers complained.

#ss-gb just watched that, thought it would have been good. It might have been but I couldn't hear a bloody word. Whispering an mumbling — Alan Bateson (@Alan_Bateson) February 19, 2017

Does anyone at #BBC listen to progs before broadcast, can't hear SS GB, whispered mumbling. sort it out auntie. — David sills (@DavidSills44) February 19, 2017

Sam Riley sounds like he smokes 5 packs a day. No idea what he's mumbling about in #ss-gb — Polly (@Pollycameroz) February 19, 2017

Watching #SS-GB, but there is the curse of the 'mumbling' again, especially from leading man — hilary fawcett (@bestboomer) February 19, 2017

For others, it was the combination of Nazi cliches and inaudible acting that was a switch off.

"Listen very carefully I shall mumble this only once!" #SSGB — Phil...... ⚒ (@pipjcee) February 19, 2017

The drama includes several subtitled sections involving German actors speaking in their native tongue. Many viewers said on Twitter that it was the English-speaking sections where subtitles were needed.

#ssgb Subtitle department should have kept it up for all the dialogue. Head melted trying to understand this. — Paula Nolan (@PaulaStrand) February 19, 2017

Wish Sam Riley would drop the husky voice ffs, me and @MikeSpikeInker have got the subtitles on #SSGB — Jenny Johnson (@JennyCardiff3) February 19, 2017

Others expressed incredulity that the corporation appears to have failed to learn lessons after the mumbling row that overshadowed the adaptation of Jamaica Inn in 2014, when viewing figures plummeted after hundreds of complaints about inaudible dialogue.



FFS, clearly a lot of work has gone into #SSGB but it's ruined by the mumbling . I think this is the worst since Jamaica Inn. — Victoria Isherwood (@VicIsherwood) February 19, 2017

The audience for the second episode of Jamaica Inn fell by 1.6 million after the initial complaints. The BBC’s controller of drama commissioning, Ben Stephenson, apologised to viewers and promised the corporation would examine the sound issues that plagued the first episode.

But complaints still dogged that series and others that have followed, including Happy Valley and 10 Rillington Place.

The BBC’s current Saturday night drama Taboo – Tom Hardy’s tale about the East India Company and the slave trade – has enjoyed better reviews, but has also been beset by viewers’ complaints about mumbling actors.

Many singled out SS-GB’s lead actor, Sam Riley, who plays the detective at the centre of the series.

A spokeswoman for the BBC said: “We take audibility seriously and we will look at the sound levels on the programme in time for the next episode.” It is understood that the complaints numbered in double figures.

SS-GB imagines what would have happened if the Nazis had won the Battle of Britain in 1941. It was adapted from Len Deighton’s 1978 thriller novel of the same name by Neal Purvis and Robert Wade, the Bafta winners behind Bond films Spectre, Skyfall and Casino Royale.

Wade said the drama was aimed at making viewers think, “What would I have done?” He added: “It’s very important that we talk about this stuff. It’s become part of our mythology that we stood alone. We did, but it was a very close-run thing. We could have lost the Battle of Britain if the weather had been different. In fact, it was miraculous that we won that battle.

“Britain was alone at that period. America wasn’t involved. They were looking the other way. It was before Pearl Harbor.”

The drama has been compared to Amazon’s The Man in the High Castle, which also imagines an alternative history in which the Nazis won the second world war. Wade has been quoted as saying: “I would make a distinction from The Man in the High Castle, which is more sci-fi and less close to what happened.

“In SS-GB, the British are living through the occupation. The game is still not over. History is alive – and that’s what’s particularly clever about this story.”

Last week, a Guardian first-look review awarded SS-GB three out of five stars, suggesting that “there has been an over-reliance on scenes of men talking and scowling in dimly lit rooms ... it would be helpful to see more of the minutiae of London life under the Nazis, to get some fresh air after being confined to the corridors of power”.