One person who isn't worried though is lead actor Matthew Rhys. Having already mastered the tricky act of playing two outwardly identical, but completely different, characters for the project, the Brothers & Sisters actor was confident when talking to Digital Spy that there will be no fingers pointed at The Scapegoat...
Can you tell any readers who are unfamiliar with the novel a little bit about The Scapegoat?
"It's about two men in varying stages in their lives who through a very chance meeting, or an alignment of the stars, knock into each other, discover they are the exact doppelgänger of each other and after a very alcoholic night swap places in life with some thrilling and disastrous results."
Although the characters look the same, they're actually very different aren't they? What were the challenges of playing two people?
"I think as an audience you have to believe that if they were to swap roles, people in their lives could feasibly believe they are the other person. However, you also have to make enough subtle differences to know that there is a difference. It's making it believable enough that he could change places, but different enough from the other one. So that is the fine balance I struggled with a little.
"There was a few mental things I did about attitude. I also have this thing with John, the posh one, [where] I'd slightly pretend I could smell something unpleasant to give that thin veneer of sneer. And you try tiny little somethings with posture, the way the two of them sit and stand, because again you can't be too different otherwise the audience is going to go, 'Well it's clearly not him'. So it was always a bit of a juggle."
Would you say because of that The Scapegoat was one of your more difficult projects?
"The majority of the drama is [me playing] one character, which is great. If you were to do two characters simultaneously and continuously, I'd have shot myself in the head, because... we were literally sort of 'coat off, coat off', 'hair comb, hair comb', 'stand here, stand here', so your head's spinning on those days. So for the most part it was an easier run in that respect."
Did you read the original Daphne du Maurier novel before filming?
"I didn't for the simple reason that I have done in the past when I've done adaptations. Just prior to Scapegoat I did Charles Dickens for the BBC and I sort of took from the novel things that weren't in the screenplay, which I think... can confuse an audience, because they'll go, 'Well what's that about?'"
Did you check out the film version with Alec Guinness?
"It's the same thing. I know if I was to watch it I would either steal things or be accused of doing that. I watched the trailer and that was enough for me."
ITV has said it wants The Scapegoat to do justice to the du Maurier brand - do you think fans will be satisfied?
"I think so, yeah. It premiered at the du Maurier festival in Cornwall this year and you couldn't show it to a more hardcore audience. But the reaction was very favourable and they said it did do it justice. We don't do the same ending, but the major themes are there and in that respect we've been very true to the novel. Apparently."
Was there a bit of a stir about changing the ending?
"When it comes to hardcore fans you're never going to please all of them. There was some disgruntlement with what we had and others enjoyed the fact that they had a new ending that they didn't know, that they had a pleasant or unpleasant surprise."
Did you hear from lots of du Maurier fans during filming?
"There was a lot of people chanting on the set, 'Why him? why him?' No, there was a bit of blogging about how it was to turn out but no influence there."
How did it feel stepping into the 1950s setting?
"It was difficult in one respect because the research I did was [to] watch 1950s films and then you find yourself becoming a caricature. So you have to make a modern version of the 1950s, because if you did what was going on [then] it's too alien now. It's making it accessible. I mean I've been playing an American [on Brothers & Sisters] for five years so coming back into an English accent felt weird."
How did you find it working with female co-stars as talented and formidable as Sheridan Smith and Dame Eileen Atkins?
"Just great. When you have a cast like that around you your game gets upped. And when you're sat in front of Dame Eileen Atkins playing your formidable mother you don't have to act much. So that was all a bit of a bonus."
Are you disappointed that The Scapegoat is no longer getting released in cinemas as well?
"All power to [writer and director] Charles Sturridge, given the time and budget constraints he had he did an incredible job making it look very cinematic and I think that's why there was original talk of putting this on the big screen. It's earned its place in that sort of cinematic way and it's a travesty it hasn't gone to theatrical release.
"I think [cinema] is a great bar to set yourself, because I think you will reach for that. It's dangerous and it's good because if you prove to them you can do [TV dramas] that well in that little amount of time and money, people will do it every time. They'll have no excuse.
"I love it when television is shot in a cinematic way and I think to aspire to that is no bad thing. If more productions do do that then more power to the British film industry, because it's certainly on a downer at the moment."
Quite a few people will recognise you from Brothers & Sisters. Do you miss it?
"I miss the cast enormously, because we had such a good time. I learnt an incredible amount on it as a project and I was given the opportunity to direct, which was fantastic. So to me it was this enormous learning curve."
Do you think the show could ever come back?
"I'd do a one-off film of it, like a TV film where we all get shot at the end, there's an explosion, alien invasion, we save the world, something like that."
Do you still get fans coming up to you and asking about Brothers & Sisters?
"Yeah. I think it did well because it was a family drama. It appealed universally... I think that's where our success lay. We weren't some high concept show, we were a simple family drama. And everyone comes from one in some sense or another, so people could relate to it."
Do you prefer working on US or UK projects?
"What I love doing most is doing both. If I can straddle the Atlantic for a bit I will be more than happy. If I can come home and do some projects and keep a toe in America, I'll be living the ideal."
Are there any current US network shows like Brothers & Sisters that you'd like to star in?
"Homeland. Bloody Damian Lewis. No, he's exceptional in it. The project I'm about to begin I'm incredibly excited about. I'm off to do a KGB spy thriller called The Americans for FX and Dreamworks. I get to run around with a gun in that."
The Scapegoat airs Sunday (September 9) at 9pm on ITV1