Instead of focusing on copycat killers, this series sees Chandler, Miles and Buchan trying to solve crimes by using historical misdeeds to give them some clues.
After watching the creepy first episode, Rupert Penry-Jones, Phil Davis and Steve Pemberton (along with executive producer Sally Woodward Gentle and director Richard Clark) came to chat to reporters about what we can expect from the show, what made Rupert feel sick during filming, and whether they're up for more series...
Do you think this series has upped the fear factor?
Sally: "We have a little bit. I think the first Ripper story was pretty scary, I think the Krays was slightly less scary. But we really like the gothic nature. I don't think there's anything genuinely scary on telly - something you can turn the lights off and just get a little excited about. It is, but at the same time it's got that black humour to it so it's never unbearable. We like to have a little bit of scariness."
Phil: "I think we're in a place almost where horror movie meets the cop show. It's in that place and you know you want to take full advantage of that potential, so it is upped, the horror factor."
Rupert: "One thing I've noticed is that every time we've gone back to filming, in the art department they have pictures of Se7en, which is exactly that thing of cop show meets the horror genre. I think Phil's right. I missed the horror that we had in the second [series]. I'm glad it's back now. It's this very gothic feeling that we get which is, I think, what makes Whitechapel special and different."
There are some gory moments in the show - are any of you squeamish?
Rupert: "The first series we did was kind of horrible because the poor girls who were playing the prostitutes who were being murdered were having to lie on the floor with real offal on their bodies, so that was horrible. But this time round it's all fake - there's no real livers and things around! There's a severed foot at one point which was pretty disgusting."
Phil: "The art department did a very fine headless corpse. We found it very difficult to film it."
Rupert: "It was too gruesome really."
Phil: "It was a bit too gruesome, yeah. We had to be politic in the way it was shot. But I'm not particularly squeamish. Were you guys squeamish?"
Steve: "I don't really get to see all the nasty stuff, although I would love to. Buchan's down in his basement and he likes the paperwork rather than the actual bodies, so unfortunately I never got to see it."
Rupert: "One of the things I think that's great about the show which we had obviously with the copycats, because it was copycatting real people - this time round you have us using the past as a map. But all the stories, all the things that we use, the past crimes, they're all real so you still get that element of real life crimes that have actually happened and some of them are pretty ghastly."
Sally: "If Claire Rushbrook who plays Llewelyn was here, she'd tell you that she's very, very squeamish."
Rupert: "She's the most squeamish."
Sally: "But has managed to conquer her fears."
What was hard about filming the headless corpse?
Richard: "It was a challenge. We used quite a lot of wide angle shots. We were in a mortuary, so the body's quite distant and far away. Then it was a matter of using detail in a slightly impressionistic way. But we had a lot of debate in the edit as to what was and wasn't acceptable and eventually found a line that we felt was about right for Whitechapel. I shot lots of stuff that was totally unacceptable, as it turned out, but I thought at least we had it in the bag."
Phil: "But, you know, any corpse that's on a slab in the mortuary is naked, so it's difficult for primetime television to shoot such things."
Rupert: "But when it's naked with no head, no arms and no legs, it's a bit much, I think."
Does anyone - the crew, the extras - ever get sick on set?
Sally: "No, but Claire genuinely was very wobbly in the first series."
Rupert: "The most gruesome thing this year I think, which I've just remembered - and I did feel a bit sick - was within the second story. We were using a fox and there's a sequence where Phil and I have to go and interview the guy that looks after the fox. But when we walked up to the cage, the fox kept running away. So what they had to do was establish that I was bringing food to the fox, but the fox eats chick heads and chick legs, so you had them chopping legs off dead chicks and heads which I had to keep in my pocket. That was pretty horrendous."
Sally: "Which, I have to say, were already dead."
Rupert: "Oh yeah, that's what foxes eat, isn't it? No animals were harmed in the making of this show!"
Steve, with your track record on The League of Gentlemen, have you ever been tempted to give tips to the Whitechapel team?
Steve: "I'm just jealous I didn't think of it first! When we were doing the first series of Whitechapel, all to do with Jack the Ripper, I was playing a similar Ripper obsessive in Psychoville. So there was a nice crossover there. And in fact I took Buchan's book of Ripperology and used it as a prop for my character David in Psychoville.
"But it was very exciting to read the first one and it's been brilliant for me to be part of it because it is a legitimate drama and I've not done so many of those kinds of things. It's a brilliant character, Buchan, because he does bring some humour into it but also has a great emotional arc through the three stories as well.
"In the first one he takes over a little bit and tries to put his stamp on the police investigation but he loses his confidence a little bit and he ends up in therapy, so there was a lot of great stuff to play in there. It's been a joy to do and it's right up my street, definitely."
Rupert - do you have a love interest this series? Do you have to get your clothes off?
Rupert: "He does grow emotionally through the show. Each story, there's a new woman that he's trying to form some sort of relationship with. But he's very new to the whole thing and it doesn't really work for him. He finds it quite hard work and by the end he does find someone he quite likes, but it's not going to work out for him really. It's the kind of character that he'll always be searching. I don't know if he'll ever find anything. And I do get a bit of kit off, yeah."
Phil: "The full-frontal nudity we didn't show you."
Rupert: "Too gruesome! In the last story it's set where they don't get to go home, so he's constantly changing his shirts. There's lots of shirts being changed."
Steve: "I didn't have to change my shirt."
Phil: "I volunteered on a number of occasions."
Rupert: "We can't be that scary!"
Do we see the relationship between Miles and Chandler continue to develop this series?
Phil: "Yes, the relationship with Chandler has changed from the very first one, when he was opposed to Chandler coming anywhere near to Whitechapel at all, made his life as difficult as he possibly could. But at the end of that story, Chandler did save his life, so he was a bit more sympathetic and there is a sort of friendship. It's still kind of an abrasive relationship and it's still kind of difficult and it does get challenged in these three stories, but they have reached a kind of strange friendship, I think."
Rupert: "He's either a big brother or a father figure for Chandler."
Phil: "Yes. And I think Miles becomes interested in Chandler and feels that he's probably lonely and would like to see him have a relationship with someone or other and is disappointed when it doesn't occur for him, so there's a bit of social engineering going on of Miles trying to give Chandler a happier life, because he is a strange guy."
What about MIles's relationship with Buchan?
Phil: "Well, that's as difficult as it ever was. Miles is very sceptical about Buchan's contribution to these investigations and if it was up to him he'd have him turfed out of the basement."
Rupert: "Part of the dynamic is that Chandler's always caught between these two and trying to get them to get along and they never do, so I'm constantly having to go from one to the other."
Can you tell us about some of the famous cases touched upon in this series, Steve? Did you know about all of them?
Steve: "I hadn't heard of the Ratcliffe Highway Murders and I read up on it a little bit. That forms a great part of the first storyline. But they also touch on stuff like Charles Manson and in the next episode there's some reference to some famous poisoners - Mary Ann Cotton and there's Dr Crippen. So it's a mixture of references, some of which you get.
"There's talk of masked killers like the Zodiac Killer and in the third story there's a spree couple who go around killing people. So for myself a lot of it, as I'm sure will be the case with viewers, you're aware of a lot of it but something like the Ratcliffe Highway Murders, which is quite specific, is not so well known.
"But as Rupert said, they're all true, they're all factual. Nothing that I come up with in terms of the factual stuff is made up, so that's great to know - that everything has a basis in reality. Fiction's never stranger than the truth. All of these stories as bizarre and gothic, as weird as they go - and it does get more strange and gothic - it's all based on real storylines. They're all inspired by these real true life crimes and I think that's part of the appeal of the show - people like to find out about them."
Do any of you have any similarities to your characters? Rupert, do you have any OCD qualities in real life?
Rupert: "I don't think I have. My wife does think I have! I like things in order, but I wouldn't say I was obsessive about it. I'm more comfortable if things are neat and tidy, let's put it like that! But I think a lot of guys are like that."
Phil: "And Miles is irascible and short tempered and difficult. As you can see, I'm nothing like that!"
Steve: "I suppose for Buchan it's the logic - that's why he's drawn to Chandler. And I am quite logical and I like things in order as well, so we make quite a good pair. You forget all these girls you've been dating - I think Buchan and Chandler is the couple!"
Do we see Chandler change at all over the series?
Rupert: "I think since the show's started he's changed quite a bit. He's kind of grown up a bit and become more confident and more manly, really. He was very much a boy when it started. And in terms of relationships with other people, he sees everybody else having a life and having somewhere to go at the end of the day's work and he starts to pine for that himself.
"So he does try to change but it's a long lonely road that he's walking and I don't know if he ever will - that's up to the writers and the producers. I think part of the excitement of the character for me is this lone guy who can't quite make his life work in any other world apart from his job."
Now that Whitechapel has moved away from copycats, there's obviously much more potential for stories. Would you be happy to stay with the show in the future?
Rupert: "Yeah, as long as it stays at the standard it's at at the moment I can't see why I would want to stop."
Phil: "I would certainly like to do some more."
Steve: "I think the third series shows that it does have that longevity because it's no longer rooted to one case or a familiar case - you've got the whole of crime history to draw upon as long as you keep Buchan in his basement!"
Rupert: "To be honest it does feel like without Buchan and Llewelyn we wouldn't solve anything. It's Buchan and Llewelyn that give us all our tips really."
Phil: "Also, seriously, there's still room for the characters to develop and they're still being challenged and I think becoming richer and more three-dimensional as we go along, so there's still some life in it yet."
Whitechapel returns for its new series on Monday at 9pm on ITV1.