The Weekend's Viewing: The Thick of It, Sat, BBC2 Homeland, Sun, Channel 4

An hour of The Thick of It and not an oath that didn't come fenced by quotation marks.

Stranger still, a good quarter of an hour of Malcolm Tucker and not an oath at all. The Bernini of the wounding obscenity, origin of some of the most thrillingly baroque execrations ever heard on television, was in unnervingly decorous form this week, curbing his speech to the formal requirements of the Goolding Inquiry, the governmental hearings into the culture of leaking that took up all of Saturday's extended episode. It was a daring departure from form – the cameras fixed and no corridor scurrying or whispered conversations – and it turned into something more fiercely accusatory than you might have expected. Every episode of The Thick of It rests on a contempt for the evasions and hypocrisy of party politics, of course, but the writers had a broader target here. In a final tirade before the inquiry panel, Malcolm turned their accusations back on them and denounced what he saw as a charade of Establishment indignation: "Everyone in this room has bent the rules," he said. "I am you and you are me."

But that detectable swerve into gravity came only towards the end of an episode that mostly relished the comic possibilities of the televised inquiry, a theatre of self-serving earnestness that we've most recently experienced through the Leveson hearings. I wasn't entirely convinced myself that any such hearing would interrogate three colleagues simultaneously, but a little bit of poetic licence doesn't hurt and pretty much everywhere else the script pinned down the absurdities of the process perfectly, as ministers and their functionaries did their best to ensure that none of the shit that had just hit the fan sprayed back on them. There was false contrition: "Others may attempt to wriggle off the hook of shame. I will not," said Phil solemnly. There were the tics of nervous self-incrimination: "I don't have a guilty conscience but I do have a guilty face," confessed Terri, shortly before going off on a rambling inconsequentiality about her brother's abused hamster. And there was that transparent switch from suave professionalism to exonerating cluelessness whenever the questions got dangerously specific.

Some of the witnesses stammered out their prevarications: "I do not recall to that," said Terri at one point. Others waved them in the panel's face: "Je ne remember pas," replied Malcolm scornfully, after he'd been presented with apparently incontrovertible proof of his guilt. And, curiously, the restrictions of the set-up pushed the cast into some of their best performances for weeks, not doing a familiar schtick any longer but suddenly off balance and under an entirely novel kind of pressure. It was both very funny and also the closest thing we've had to serious political drama on television for far too long.

Last week's big enigma in Homeland was why Carrie bothered to re-dye her hair blonde while she was still in the field in Beirut and, you might have thought, had a lot more pressing things to do. This week, the mystery was why Abu Nazir would insist on Brody jeopardising his cover by sending him to rescue the group's bomb-maker, whose cover had been blown. You have an agent with access to the highest levels of the American government, a man who has just saved you from a CIA assassination and is a national celebrity ("Hey. Ain't you that guy who was rescued from the Ay-rabs?"). And you send him to a place that will shortly be crawling with Federal agents on a mission that could be accomplished with one telephone call? From that point things got worse with comical rapidity until Brody's day ended with him hosing blood and mud off himself in a public car wash. I'm beginning to wonder whether this plot was devised at one of the real-world locations glimpsed in last night's episode – the George Bush Center for Intelligence.

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