The Weekend's TV: Camelot, Sat, Channel 4 <br/>James May's Toy Stories: the Great Train Race, Sun, BBC2

Not one of their better knights

I'd better confess to a disability before tackling Camelot, Channel 4's new Saturday night drama.

It's a strange one. Beards on television? No problem at all. Similarly swords on television. I'm perfectly capable of maintaining a dispassionate lack of prejudice. But combine the beards with the swords and I begin to have real difficulties keeping a straight face. If you then drape the beardy swordsmen in dead animal skins and add ecclesiastical dirges on to the soundtrack, I'm in real trouble. It's better you know, frankly. I understand that a lot of people love these things and that Game of Thrones already has a following that is positively cult-like. But I feel like a colour-blind man looking at a Farrow & Ball paint chart.

Camelot obeys several of the basic rules of the genre in its modern form. There must be sex, for one thing, and not just discreet sinking-out-of-the-frame-type sex, but the nipple-flashing, buttock-revealing kind. So we first encountered Arthur as he lay stark naked on a river bank with an obliging local wench, trailing an approving finger across her haunch. There will also be bad language, or rather language pointedly at odds with the cod High Style that used to be de rigueur in these things. When an onlooker doubts that Arthur will be able to pull the sword from the stone, Merlin doesn't say, "Begone, low churl." He says, "Piss off." There will also be – and this really makes it tricky to control the giggling – a lot of Glowery Gothic, a style of acting in which everyone looks incandescently furious all the time.

I suppose if you're Morgan Le Fay you might feel you had good reason to be cross. Camelot began with her return home to her father King Uther's court and it wasn't a jolly reunion. First of all he punched her in the face because she called his wife a horse, and then he disowned her and threw her out. So Morgan – played by Eva Green – shape-shifted into a serving girl and poisoned him. Danny Kaye came to mind: "The pellet with the poison's in the vessel with the pestle; the chalice from the palace has the brew that is true." Then I realised that Danny wasn't helping and tried to concentrate, not assisted in this task by James Purefoy's decision to give the villainous Lot (who joins forces with Morgan) an evil cackle of Brian Blessed dimensions.

Merlin (Joseph Fiennes) bucks the conventions a little, since he looks nothing like Dumbledore at all but is played as a cross between an East End enforcer and Alastair Campbell. There's even a hint that he may have rigged the succession, by putting the sword in the stone himself and spreading the story that its removal is the only guaranteed sign of legitimacy. If so, he certainly has an eye for public theatre, since he's wedged it into the lip of a 200-foot high waterfall that Arthur has to climb first, giving floating voters plenty of time to assemble for the big finish. That comes later though, after Arthur has been introduced to Camelot and a rather ragged band of supporters. "You've got everything here... there's so much potential," said one of his sidekicks, looking around the ruined walls. "You sound like Merlin," replied Arthur. Well, no. He sounded like an estate agent. Available for immediate viewing: Seat of National Revival. Excellent cliff-top position and spacious dining area. In need of modernisation.

You may feel this shows scant regard for our national myth, a narrative that has fed into great literature from Malory to Tennyson. To which I'd reply that Camelot doesn't show a huge amount of respect either, and that unconstrained solemnity about the Arthurian legend can turn out far worse than levity. You can think of Danny Kaye while watching this jolly tosh. Or you can, as I did at one moment, think of Himmler, a big Arthur fan-boy who built Wewelsburg Castle as a kind of Tuetonic replica of Camelot. When you hear a line like "We're in a fight for our lives for the soul of this country" uttered with solemn urgency, you catch just a whiff of that gamey scent of national purification. Better to giggle, I think, than take it seriously.

There was a very different account of patriotic values in James May's Toy Stories: the Great Train Race. "This is what makes Britain great," he said proudly, and he wasn't talking about kingly virtues or knightly fealty but the willingness to get up early on your day off and help lay a model railway line from Bideford to Barnstaple, 10 miles on the map but a scale distance of 700 for the miniature engines that were going to make the run. An earlier attempt to pull off this feat ended in failure, after all the toy trains broke down. For this re-run May had tweaked the format a little, challenging a group of German model-railway enthusiasts to a head-to-head race with three different types of train – antique, modern and a futuristic design that had to have an on-board power source (the Germans, helpfully, had fuelled theirs with alcohol brewed from sauerkraut). To be honest, the charm of the thing ran out long before the trains made it to their final destination, despite an attempt to dress up minor hiccups along the way as moments of nailbiting tension. But it did have real charm to begin with. It's unnerving, but I really liked James May's Man Lab too. I think I might be turning into a bloke.