Last Night's TV: Wonderland, BBC2<br/>Summits, BBC4

There's no such thing as love at first byte

"I really put my personality into this character," said Carolyn about her Second Life avatar, a pixellated alter ego that represents her in virtual space. Judging from the avatar's appearance, Carolyn is not a shy woman, happy to showcase her imaginary DD breasts and porn-fantasy figure in sword-and-sorcery bondage gear that even Cher might denounce as immodest. It would be ungentlemanly to comment on whether this on-screen presence is better-looking than the flesh-and-blood woman who created her, but if you wanted to rendezvous with Carolyn in the real world and relied on her Second Life avatar to help you recognise her, you'd probably be waiting quite a while before you got hooked up. Still, the goth-rock babe with the rather wooden gait was attractive enough to make the crudely rendered eyes of Elliot's avatar dilate tellingly when he bumped into her in cyberspace. Elliot, incidentally, has a heavily tattooed Schwarzenegger torso and likes to stroll around with two Uzis and a sword. And when Elliot's avatar met Carolyn's avatar, it was love at first mouse-click. You could say they were made for each other.

Wonderland's film, Virtual Adultery and Cyberspace Love, began with Carolyn's melancholy husband, Lee, recalling the early clues that not all was well in his marriage. "I knew something was going on when I wasn't allowed into my own bedroom," he said, and before long Carolyn had confirmed his suspicions. "I want to do and see and experience things that I can't when I'm married to you," she told him, explaining her marathon sessions online, during which she remotely canoodled with Elliot and went off on dates to a Miami Vice-style restaurant with its own attached dolphinarium. Lee didn't much care for this and his children absolutely hated it, but Carolyn, one of those people who describe their own prevarications with a whinnying laugh that is supposed to be disarming, was obsessed and didn't care. After a while, she was spending up to 14 hours a day on the computer while all her real-world emotional connections fizzled and died.

It needn't work that way, though. "Kira", a lad-mag-cover blonde, and "Nik", an indie-rock dude, also met in Second Life. In what virtual worlders call "meatspace", Kristen and Steve, their creators, both looked as if something had gone wrong with the aspect ratio – they were considerably broader and squatter than their Second Life proxies – but the mutual attraction had survived the first face-to-face meeting and they still clicked, even without a mouse at hand. They'd even got married in Second Life, a ceremony attended by an implausibly attractive congregation of friends and, unless my eyes deceived me, a large rabbit. As the mother of the bride looked on fondly from her laptop, the couple exchanged vows, blissfully indifferent to minor problems with lip-syncing and object clipping. Things didn't go as well when Carolyn finally met Elliot, but she didn't appear to have learnt anything from the experience. "I wish I could feel connected and in love and hopeful back in my marriage again," she said sorrowfully. "If I could switch a button, that's what I would do." Congratulations on your good intentions, Carolyn, but that only works for computer-generated people.

It wasn't entirely helpful that I watched Wonderland before looking at Summits, BBC4's new series about critical moments in international diplomacy, because I couldn't help noticing something avatar-like about David Reynolds's presentation, with its mechanical hand gestures and carefully rehearsed emphases. The programme itself was pretty good, though, a detailed account of Neville Chamberlain's attempt to forestall war in Europe, which Reynolds identified as the origin of modern summitry. It's a great subject, knitting intimate psychology together with the fate of nations. Chamberlain, Reynolds argued, was driven by a desire to match the achievements of his father and brother, who both aimed at the premiership but never quite made it. And Chamberlain's dizzy sense of success after the first meetings with Hitler probably contributed to his fatal conviction that the German Chancellor could be trusted to keep his word. "Now as Prime Minister, I have only to raise a finger and the whole face of Europe is changed," he wrote to his sisters, evidence that there wasn't a monopoly on megalomania when the two men met.

Reynolds's hour-by-hour account of the negotiations was engrossing and occasionally excruciating, not because the tension rose too high but because he sometimes coloured his third-person account of the conversations with first-person histrionics, channelling Hitler and Chamberlain through the person of a bespectacled and balding Cambridge academic. He's not the first telly historian to get tempted by am-dram – Simon Schama is prone to drop into character while quoting a historical document – but it doesn't work any better for him than it does for anybody else. Hide your eyes and hum loudly through those bits, but the rest is fascinating.