Last Night's Television: Who Needs Fathers?, BBC2<br />Canoe Man, BBC4

Fondly looking at video footage of his four sons, Alex voiced a commonplace of parental fondness. "They make it all worthwhile," he murmured. "All the shit, all the crap." The irony in this case being that without his boys, Alex's portion of shit and crap would be a fraction of what it is. Alex and his partner, Juliette, couldn't bring themselves to stay together for the sake of their children but – for the sake of the children – they can't now make a clean break either. And that's where the crap bubbles up from – the septic fissure in their own cracked relationship. They provided one half of a sharply contrasted pair of case studies in Who Needs Fathers?, the first of a series about broken homes, and they conspicuously weren't the ones you'd have filed under the "How To" heading.

For that, you had to turn to Chris and Angela, struggling to manage their separation and keep their children happy without resorting to the family courts. The theory is easy, of course. Put the children first, their happiness is paramount. What's a lot harder is the practice, and Chris and Angela offered a pretty impressive example of how it might be achieved. Both seemed to understand that their children shouldn't find themselves torn beneath their parents and that a brisk civility at the point of handover was essential. Both pointedly instructed their children to consider the other parent at the moment of departure ("Give mummy a kiss"), a tiny gesture of recognition but a significant one. And even under the pressure of strained finances, Chris and Angela appeared to keep their tempers and compromise for the sake of their children. It wasn't a happy situation exactly, but it was one where the sadness seemed to have been minimised.

Alex and Juliette couldn't have been more different, though exactly who was to blame for this it wasn't easy to say with any certainty at first. We approached the battle zone from Alex's side of the lines, experiencing his frustration and rage as he attempted to arrange the first holiday he'd had with his children in four years. As the clock ticked away to his departure date, Juliette refused to hand over the children. The police were called and went away saying it was a matter for the courts. The next morning, Alex enlisted a sympathetic female friend to help broker a deal and tried again, with no luck. Sitting in his car, he wept at his helplessness, and you had to remind yourself quite forcefully that you hadn't heard Juliette's side at all. When you eventually did, she didn't do herself a lot of favours. "He would not give me confirmation of where those children were going," she insisted. "Didn't he come back in the morning once you'd got those documents?" asked an off-camera voice. "No," Juliette replied.

Either the sequence we'd seen earlier was shockingly misleading or she was telling a bare-faced lie, unaware that there was a film record of her husband doing precisely that. For some reason, the producer didn't let her know that she'd just been busted, perhaps calculating that she needed a few more yards of rope to make an effective noose. Juliette carried on tying knots. "He has me in court probably every two or three months," she sighed wearily, apparently unable to conceive that we might read this as evidence of her intransigence rather than his. And in the middle were four little boys, trying to work how to live their lives. A title card revealed that after another 13 months of legal wrangling, Alex and Juliette had come to a workable agreement. It probably cost them a small fortune and I bet it's not a patch on the one that Chris and Angela had worked out for themselves.

Canoe Man, Norman Hull's drama about the fraudsters John and Anne Darwin had an excellent plotline and a terrific cast (Bernard Hill and Saskia Reeves), but for some reason came up as less than the sum of its parts. The story was part of the problem, I think, mechanical exposition taking up quite a bit of the time, and leaving not a lot of room for psychological exploration. But the look of it didn't help either – a flat, overlit sharpness that kept on reminding you of Crimewatch reconstructions, not exactly an apogee of dramatic art. The crux of this tale wasn't why John Darwin might want to fake his death and run away. It was how his wife could have sustained the fiction of his death in front of her grieving sons. To that, Hull didn't really offer an answer, just some unconvincing voiceovers: "As difficult as he was to live with it would have been even more difficult to live without him," said Anne. Always be suspicious when you hear a voiceover in a television play. It's just too useful as dramatic duct tape, sealing over the cracks.