Why now? Clattering slightly in his chain mail, Arthur is gung-ho under fire. "We are on the eve of the millennium and the time is right for me to come back," he says, playing blithe politician to my dogged Paxman. "People are aware of a new age." Not to be outdone, Guinevere, still wearing the perm that launched a thousand pre-Raphaelites, pipes up, "It's a very mystical time". Partly, they're here to set the record straight after suffering the indignity of imperfect impersonations. "No one ever consults us," harrumphs Arthur, who is underwhelmed by most fictional attempts, notably Thomas Malory's paltry effort. "Morte d'Arthur? Nonsense. I didn't even speak French."
As for the recent, egregious First Knight, Guinevere concedes that Sean Connery had a good stab at her husband's accent. Surprisingly, until comediennes Maggie Fox and Sue Ryding (aka Lip Service) created their shatteringly authentic docu-drama, King Arthur and the Knights of the Occasional Table, their favourite was the film Camelot. "Although Vanessa Redgrave was a little tall," muses Guinevere. "The amount of smoke everywhere was very accurate," approves Arthur. "Many people don't realise that a lot of our conversations were underscored. You couldn't actually hear yourself speak. And that marvellous song, `How to Handle a Woman'. I learned a lot from that..."
Bull's-eye! It's out in the open: the marriage, the affair, the whole kit-and-kaboodle. It still rankles. They were reminded of it when they visited this year's Glastonbury festival. "We invented that, David," says Guinevere. She'd had it up to the back teeth twiddling with her tapestry from cock-crow to candles-out, and dreamed up an open-air event with music, dancing and face-painting - not much more than the colour blue originally. "This year they had an acoustic stage. Well, we had that, not to mention the mud and the queues for the toilets." Which is where the trouble started.
After queuing for two days, Arthur returned to the tent and immediately sensed something wasn't right. "There was my sleeping bag with a hot water bottle in it. Well, it certainly wasn't mine." There was a heart on it, which Arthur suspected as being of French origin. "Then there was this long, pointy, shiny, hard lance, which made me think something was going on. Also, there were these initials on it, `L du L'. I was still a bit foxed, but then I realised it was Lancelot because he was actually lying in the sleeping bag next to us. Which was a bit of a shock because Lancelot was my best friend and he'd just slept with my wife."
Understandably, he threw a bit of a wobbly - "more of a screech, actually" - and then everything went to the bad. Wouldn't a couple of sessions with Relate have sorted it all out? "I couldn't talk to her because she was banished," he replies, testily. So, aside from a postcard from Lancelot, that was that.
I go for the jugular. Does Guinevere regret her folly? "David, we were doomed. Doomed to love. And you can't fight your doom. That's the thing about being a legend, you're doomed to do all kinds of things and you've just got to go with the flow. I mean, look at Arthur. One minute he was a half-clad, pimply youth, a nobody, he comes across this sword in a stone and what-not, suddenly, he's king of all Britain."
Last heard of snoozing under a hawthorn tree, it's Merlin who has masterminded their return. "He put me on-message with some slogans. Obviously, I'm not at liberty to say who he is now, but he has helped someone else rise to power in an election. The image has altered. He's dropped the droopy beard and the long hair. And the owl. It used to work, perched on his shoulder..."
But what about the real issues? Such as the round table. "When we set up castle, we didn't have a stick between us," explains Guinevere, "we took what was on offer. That table was my Dad's, it was in his garage." Ikea? "No, but it was flat-packed." It was certainly a bit of a boon when catering for all those knights. Arthur agrees. "Sir Percival, Sir Pellinore, Sir Perfluous, they all went off in search of the Holy Grail, but it was a bit of a poor do because they came back empty-handed. Not even a beaker." But the table? "It had this hole in the middle, the fore-runner of the Lazy Susan, that thing you put your nibbles on and whizzes round. In our day, we had a serving person in the hole."
Is there anything from the modern world they would have liked? "Lino," says Arthur. "Nice wipe-clean surface." Guinevere nods. "Rather like your Home Front, we did a lot to our castle ourselves. We used a lot of hessian, too, but we had it on the floor."
Guinevere is considering a beauty book with tips on How to Ride Side- Saddle in a Long Frock and Perm or How To Wash Up In Long Dangly Sleeves. They've even been on the sofa with Julia Carling. "These models," smiles Arthur, "gorgeous cheek-bone people. We were in our chain mail and they were agog, wanting to know where we got it." Two thousand years old and still at the cutting edge of fashion.
`King Arthur and the Knights of the Occasional Table' is at the Assembly Rooms (0131-226 2428) to 30 AugReuse content