Homeland, Series 4, Channel 4 / The Code, BBC Four

It was tempting to assume that Homeland [****] had died along with Damian Lewis's Brody, last seen dangling gruesomely from a crane in Tehran at the end of series three, but this tense and uncomfortable season-opener suggested that all may not be lost.

At front and centre was the question of the legitimacy of killing the enemy at long distance by remote control (in Homeland's first series, it was a drone attack which triggered Brody's revenge mission against the USA). Mathison's team had been enjoying impressive results thanks to intelligence being fed to them from the CIA in Islamabad, but this time she authorised an air raid from inside her computerised war room which killed 40 civilians at a wedding party. The fallout was catastrophic.

A parallel plotline involved Aayan, a Pakistani medical student who survived the wedding massacre and had a video clip of the assault on his phone. Once this went viral, CIA chief Lockhart (Tracy Letts) was screaming for heads to roll (not his own obviously). Carrie found herself not only in the political firing line but also being bitterly harangued by the pilot of one of the US bombers for being sent on a mission of mass murder ("you're fucking monsters, all of you"), while the formerly merciless Black Ops specialist Peter Quinn (Rupert Friend) has begun suffering chronic symptoms of cloak-and-dagger fatigue.

The moral darkness of her intelligence work has seeped fatally into Carrie's private life, such as it is. She's doing her best to forget that she ever bore Brody's baby, which she has unceremoniously dumped on her sister back home, and when she isn't bombing jihadists she has to knock herself out with drink and sleeping pills. Meanwhile her old Agency mentor Saul (a melancholy Mandy Patinkin, pictured above) is struggling to work up any enthusiasm for his new private sector job of selling weapons to the Pentagon. He delivered a mordant summary of the Afghan war to some potential clients, and how it had been crippled by a lack of long-term planning: "It was a one-year war, waged 14 times."

Danes, as ever, was magnetic, and lingering shots of her face as she registered shock, despair or anguish were more eloquent than reams of dialogue. It makes you wonder if the actress is getting a little too intensely wrapped up in the role.  Adding to the tally of woe was the ghastly fate of Islamabad CIA man Sandy Bachman, which means we won't be seeing any more of the very watchable Corey Stoll, who you may recall as the doomed Peter Russo in House of Cards.

In contrast, BBC Four's latest imported drama for Saturday nights, The Code [***], isn't exactly cheerful - it's quite grim, in fact - but at least it defies you to take it too seriously. The trigger for its thriller-conspiracy plot is the death of an aboriginal girl - did I mention it's Australian? - in a mysterious road accident in the Outback. Reporter Ned Banks (Dan Spielman) gets on the case, and is soon embroiled in a murky web of internet hacking, government secrecy and the antics of the unpleasantly Gestapo-like Cyber Crime Unit. The threat of some sort of Doomsday scenario looms in the distance, courtesy of the sinister Physanto corporation.

It suffers too much from echoes of stuff you've seen before, from Secret State to Edge of Darkness, while the fancy on-screen overlays of computer data are too brazenly post-Sherlock for comfort. But the Australian scenery is stunning, in a forbidding sort of way, while Ashley Zukerman's performance as the mentally unstable computer genius Jesse (pictured above) adds splashes of off-the-wall colour.