The first season, on which Atwood worked as a consulting producer, features departures and developments from the novel. Some characters' trajectories are altered or expanded, back-stories are fleshed out and cliffhangers adeptly inserted. In a key change, Serena is younger, not afflicted by arthritis and with a hint of Claire Underwood evident in her cool, blonde, ramrod-straight wife.

The drama depicts Gilead as a country drained of colour, an eerily quiet place rendered in muted greys. Women's status is denoted by the colour of their clothes: red for the handmaids, blue for the wives, browns for the servants – the Marthas – and the Aunts who oversee the handmaids. By contrast, the world recalled in flashbacks is cast in warm tones. For Offred, the past is sometimes tantalisingly present: her life with Luke (O-T Fagbenie) and their daughter, her friendship with Moira (Samira Wiley).

In this toxic new world, fertility is a rare and prized commodity. Women with viable ovaries have been conscripted into the service of the state, assigned to the households of the elite to produce the next generation.

"I believe that they were initially going to go for an older woman, but they changed their minds, which is thrilling for me," says Strahovski. "It adds an amazing chemistry between Offred and Serena because you have these two women who are of the same age pitted against each other. One has power and one does not and I think that the idea of fertility (as an issue between them) is very fresh. It adds a lot of meat: there's jealousy and hopefulness and anger, all kinds of juicy things that we can play with together."

The series has also given Serena a back-story which suggests that, in spite of her status, she too has lost her voice and her power. "I didn't want to be a character that you could easily hate," says Strahovski. "It was important to me to humanise her, which ended up being a bit of a task because she's obviously unpleasant and incredibly brutal. I really had to peel back layers and get into what made her tick, what was her vulnerability and what was at the core of her heart.

"There were a lot of conversations with Bruce Miller about allowing Serena vulnerable moments, so that she's not just icy, even though she is icy a lot of the time. The notion of rejection kept coming up: she's no longer able to work, to read and write, or to connect to her husband intimately. That strips her of so much of her identity and, when you add infertility, it leaves her in a sad, bitter place."

Strahovski, who hadn't read the book before her audition, says, "The pilot was so well-written: there was so much sub-text. It's a dream come true if you have a script that's dripping in the unsaid moments: it's all in the nuances. Every little twitch and blink of the eye counts and every breath means something because it's so constricted. The walls are so high that any little movement that isn't part of the rule book is noticed."

Miller explains that the environment of extreme repression "really lends itself to the thriller genre. Offred is constantly in mortal danger and violence can come at her from any direction. That's the core of the show."