The dark, twisted world of psychopath Paul Spector returns to SBS this week with the launch of the second season of British crime drama The Fall.

Spector, played by 50 Shades of Grey star Jamie Dornan, is on the run wanted for murder but he still has business in Belfast. Part of it involves playing with the mind of his pursuer, Det. Supt Stella Gibson (Gillian Anderson).

Allan Cubitt, creator and writer of The Fall and for this season its director, sympathises with people who find Spector disturbing. On one level, Spector is totally normal — he works as a bereavement counsellor and appears to be a good husband and father to his two children. But on another, he is a stalker of women, invading their homes and ultimately killing them.

“There is a constant threat from Spector and I understand that his presence is deeply unsettling,” Cubitt said. “It is because you sense that something awful is coming.

“One of the things I was pleased with was the scene in the first season when he breaks into a house and moves a cup of tea. It is one of the most frightening things because he is messing with people’s minds, he is getting under your skin.

“I think another reason The Fall has been so unsettling for people is that you are invited to spend time with this person. In the conventional shows you don’t do that but then you never understand the psychology of the killer either.

“I am laying out his psychology right from the very beginning when he leaves his children on their own and is out burglarising someone’s house, and it is a fetish burglary, that is indicative of a lack of responsibility and a psychopath’s lack of awareness of the consequences of his actions.”

But it is not just Spector’s character that Cubitt explores. He also slowly reveals more of Gibson’s backstory in season two.

There is a clue to what may come in seasons two and three in his explanation of the title of the series.

“It came from Paradise Lost really, from the notion of a fall from grace. Obviously it is Spector’s fall but also Stella’s to some degree,” Cubitt said.

“It was the notion of Lucifer beginning as an angel and falling to Earth and becoming a devil, and so it links to my ideas about what children are like when they are first born and then what happens to them thereafter.”

The role of Gibson was not written with Anderson in mind but Cubitt said she quickly became the obvious choice for the role.

“My starting point with Stella was to avoid the usual baggage that I think these characters in TV dramas often have — their failed marriages, or their alcoholism.

“I thought in the first season I would not tell the audience very much about Stella at all; I would just allow them to get to know her little by little. And that enigmatic quality is something that Gillian is particularly adroit at playing.

“In all kinds of small moments she reveals deep feelings in Stella but she recognises that as a professional she has to keep them under control. As you watch season two you will see more of her emotional life emerging.”

Cubitt says he did not expect The Fall to be renewed for a third season. It has been and Anderson and Dornan have both signed on.

“I always hoped to get the first two and that continued the story up until the point where my original thoughts had got me,” Cubitt said. “Now there is season three . . .”

The Fall starts on Thursday at 8.30pm on SBS