Gripped by the dark power of Homeland The series is based on an earlier Israeli TV production - Hatufim, or Prisoners of War - created by Gideon Raff (an executive producer on the US show). Hatufim focuses on the very real suspicions faced by returning Israeli prisoners that they may have given up sensitive information, and the difficulties of reintegrating into their families and society. The main characters in the original are two prisoners who have been held for 17 years before being released. "Clearly we owe a lot to the Israeli series, but we took it in a different direction," Alex Gansa, the executive producer, has said. Danes's character, for example, did not exist in the earlier series. The result has drawn comparisons to 24, the hit series on which Gansa and Homeland's other executive producer Howard Gordon worked, but the similarities are superficial. The action in Homeland is mostly psychological, with roots that wind deep into the American psyche, through the heart of the nuclear family and the political system. It has even been suggested, in the New Yorker, that Homeland serves as an "apology" for the gung ho certainties of 24 - among which were "the notion that torture is the best and only way to get information" and "that Muslim faith and terrorist aims overlap by definition." Lewis said recently that he made it clear from the outset that he would not accept the role of Brody if lazy parallels were drawn between violence and Islam. The archetype of the indestructible lone CIA agent, embodied by Kiefer Sutherland in 24, has also undergone a transformation. Carrie we learn is self-medicating - and hiding - a bipolar condition. She's also driven to seek casual sexual encounters, especially at times of high stress. As Gansa has said, "We were very, very adamant at the beginning of Homeland that Carrie wasn't going to pick up a gun, and that we were going to tell a much slower-paced psychological story, rather than an action story." The fact that Homeland was made for the US subscription cable channel Showtime, the HBO rival responsible for Dexter, Nurse Jackie and The Borgias, meant that the makers could take many more risks with the material than if it had been on network US television. This is evident in both its sophistication and its treatment of sex and mania. Carrie is driven to follow her suspicions of Brody into his most private moments, illegally employing a CIA contractor to put him under surveillance at home. This leads to some of the series" most uncomfortable scenes, placing Carrie - and the viewer - in the role of voyeurs. Brody, meanwhile, although he continues to play the all-American hero in public, has been tortured and is suffering from flashbacks and nightmares about his time in captivity. Lewis says he drew heavily on Brian Keenan's memoir of his years as a hostage in Lebanon, An Evil Cradling, for the role. Homeland turns on the spectre of terrorism from within (and without). "We play on people's fears," says Gansa. It could be compared to the 1962 film The Manchurian Candidate (based on Richard Condon's 1959 novel, written at a time of Cold War paranoia), in which a sergeant captured by Soviets in the Korean War is brainwashed into becoming a Communist assassin. But it also bears similarities to Francis Ford Coppola's 1974 thriller about a paranoid surveillance expert, The Conversation. In Homeland, the paranoia has been relocated to the viewer's mind. We're left to decide whether we're watching the security forces sleepwalk through the formative stages of another attack on the US, or if the threat is only in the disturbed mind of an agent traumatised by her guilt about 9/11. But this is just one of Homeland's many secrets, revealed in a sequence of twists and turns that, with a second season on the way, have perhaps only just begun. Homeland starts on Channel 4 Sunday at 9pm