Last night was the middle instalment of Married at First Sight (Channel 4), the one where they actually get married. In this series – based on a Danish format which has already been adapted in the US – four strangers have been grouped into two couples based on certain scientific assessments (which don’t figure much in this second hour, so let’s not trouble ourselves) of mutual compatibility.

This would have made for dull television – like watching two wedding videos back to back – were it not for the supremely odd fact that the brides and grooms were meeting for the first time at the altar, surrounded by friends and family members who have failed to talk them out of this “daring social experiment”.

“It’s kind of like going to someone else’s wedding,” said Emma. She is marrying James, who she doesn’t know from Adam, but according to evolutionary anthropologist Dr Anna Machin, “their personalities and IQs are pretty much identical”. I’m obliged to take her word for it that this is a good thing.

Kate and Jason are also getting married at first sight, and are also deemed to be strikingly similar. Kate’s parents are being weirdly supportive (Emma’s dad, on the other hand, declined to take part; we can only guess what he thinks of the whole business).

“I think you’re both so courageous,” said Kate’s mum to Jason beforehand. Even more than the principles, it’s the near relations who appear to be sleepwalking into this foolishness. “I was aghast,” said Emma’s mum, describing her reaction to the idea. But on the day, for reasons that are not apparent, she is cool with everything.

In both cases a supremely awkward moment loomed: the point when two people must endure a wedding ceremony standing next to someone they have only just clapped eyes on. I can attest that getting married in front of people is embarrassing enough when you do it with someone you know. I can’t imagine going through it with a stranger, on TV. Perhaps it’s easier.

“We often say marriage is just the beginning,” said Emma and James’s registrar, “and it’s never been so true as it is now.” It struck me that if one of them were an immigrant, the Border Agency could burst in, stop the ceremony and quiz them about each other’s likes and dislikes. And somebody would be going back where they came from.

It was about as awkward as one could imagine, but also surprisingly sweet, with Kate and Jason holding hands, and Emma losing her voice halfway through. The vows didn’t quite make sense in the circumstances. “I give you this ring as a symbol of my commitment.” What are you talking about? I just MET you.

“That was intense,” said Jason afterwards, and I have to agree. Those in attendance seemed prepared to treat both marriages as entirely genuine, and so did both couples. Strangely, I found myself rooting for them.

“Now it’s over to them,” said Machin, all dressed up. “They’ve got this really solid foundation to build on.” Awww. Wait, no they haven’t!

The most honest moment came when James found himself dancing with his mum at the reception. “Do you like her?” she asked. “So far, yeah,” he said. I don’t cry at weddings, but my breath ran a little ragged at that point.

We demurely left James and Emma and Kate and Jason to it in their honeymoon suites. Next week I expect the wheels to come off, but here’s hoping.

The Shannon is the longest river in the British Isles, a fact I’m certain will be useful to me at some future point. In Ireland’s Wild River: The Mighty Shannon (BBC2), naturalist and cameraman Colin Stafford-Johnson explored its backwaters and wildlife by canoe. Stafford-Johnson is possessed of a contemplative nature and some really good lenses. The footage was stunning, especially the slowed-down bits of a kingfisher feeding.

Things proceeded at a gentle, almost informal pace, across four seasons. I was reminded of that Slow TV programme that consisted of a real-time canal journey but I loved that, and I loved this: bats, corncrakes, grebes, squirrels (red ones; the greys never made it across the Shannon), swans, all rendered so gorgeously as to seem exotic. You couldn’t call it sedate – not after you’d seen the pikes mating. It finished with an extraordinary sequence featuring giant starling flocks, rolling like a drunken fingerprint across the sky. I didn’t make that up. It’s the only line I remember from a poem by Richard Wilbur. I knew it would be useful one day. “It’s better not to analyse things like this too much,” said Stafford-Johnson. “Sometimes you just want to sit back and enjoy.” If you missed this, I urge to you seek it out the next time you’re in that sort of mood.