The Weekend's Television: Ross Kemp: Return to Afghanistan, Sun, Sky1Good Arrows, Sat, ITV4Charles Darwin and the Tree of Life, Sun, BBC1

No time to play soldiers

"Hi, I'm Ross Kemp," said the caption on a caricature at Kandahar air base. "Buy an H4H wristband, or they send me back to Afghanistan."

The pitch was for a forces charity, and it obviously hadn't worked, because walking past the poster was Kemp himself, lowering the price-per-wear of his off-the-peg flak jacket with Ross Kemp: Return to Afghanistan, a follow-up to Sky's very successful marriage of celebrity "journey" and front-line vérité. Audiences liked the first series, as did the squaddies themselves, reportedly, and, one must assume, the Queen's Light Press Officers. He wouldn't be back there if not, because this isn't the kind of conflict where you can take a taxi to the front line. Effectively, Kemp is an embed, and, just to underline the gravity of what he was embedding himself in, he began with a little sequence in front of Camp Bastion's war memorial, a disturbingly permanent-looking structure, which, he explained, would have to have another 20 names added to it to bring it up to date.

It had the feel of insurance footage, that, a down payment against the awful possibility (from a television producer's point of view) that there might not be any incoming fire. If so, they need hardly have worried. Kemp was held in the base at Musa Qaleh for a day to acclimatise to the 45-degree heat and then went out to join Delta Company of 5 Scots on a four-day trawling expedition through the local maize fields, an environment that is unhelpful to a cameraman hoping for wide-open vistas of the battlefield, but very congenial to the lightly armed insurgent planning an ambush. "Fields of view down to five to eight metres... if you're lucky," said the Major, briefing his men on their coming excursion.

It can't help the nerves that patrols usually know when they're about to be hit, monitoring the Taliban radio for clues about the enemy's plans. "Next couple of hundred meters, we're expecting a contact," Kemp said, in a foreign correspondent's sotto voce, and shortly after that, everyone was in the dirt showing an intense interest in the Afghan topsoil. Once the firing started, you essentially got a botanist's view of the landscape and a proctologist's view of the star, the camera lens either jammed into a nearby tussock or hard up against a pair of expensively insured buttocks. And if the underwriters were watching, this footage will surely have them reconsidering the premiums. Every time Kemp lifted his head to do a piece to camera, there would be the zing of a passing bullet, a proximity to fire that he initially seemed to find invigorating, but then clearly decided was getting to be too much of a good thing: "Woah!... woah... fucking hell!" he said, after a particularly close call. The Taliban declined to woah.

There were times when you wondered what the troops made of their guest. "Heh, heh, heh... living the dream!" he exclaimed, after dashing across an open space to tumble into a compound where the company at last had some decent cover. It was the kind of adrenalised flippancy that presumably wears off if you've got to go out on patrol day after day, and might possibly be a bit wearing once it has. But it also captured something true about the experience and the risk that wouldn't make it through the sober restraint of a news reporter's piece, and it wasn't faked. I suppose you might describe Kemp as an armchair warrior, but if you did, it would only be fair to acknowledge that he's pulled the armchair a damn sight closer to the fire than most of us would ever care to get.

Good Arrows, Dean Cavanagh and Irvine Welsh's pastiche documentary about a Welsh darts champion fallen on hard times, contained one very good performance, from Jonathan Owen as the "Beckham of Darts", and some nice lines. "What makes you think you'll get cancer, Andy?" asked the off-screen director at one point. "Well, cancer's very popular now, isn't it?" Andy replied witlessly. Unfortunately, there were too many performances that couldn't quite match it. As his mercenary wife, Big Sheila, Katy Brand treated every scene as a sketch, rolling her eyes and milking the gag in a way that completely disabled the attempt at low-key documentary realism. As a result, the dart hit the wires and bounced out.

Charles Darwin and the Tree of Life – something of a beginner's guide to natural selection – ended with a deeply gratifying scene, as the statue of Richard Owen, a double-dyed villain of palaeontology, was winched from pride of place on the staircase at the Natural History Museum to be replaced by the statue of his rival, Darwin, something close to a saint of modern biology. Not everyone is up to the humility evolutionary theory demands of us, but David Attenborough is, and he made the case well.