An ancient secret society; a demand for a papal apology; and a network of hidden tunnels. Strange things have been stirring in Hertfordshire recently. Oliver Burkeman goes in search of the Knights Templar and, perhaps, the cup of Christ.
One of the problems with secret societies - especially the kind whose members exert a shadowy influence on the course of world events - is that they can be a bit difficult to track down. Never was this more true than of the Knights Templar, the ancient Catholic order rumoured, among other things, to know the whereabouts of the Holy Grail. Officially, the Templars don't exist, having been driven underground by the pope more than 600 years ago; in The Da Vinci Code, they are described as inhabiting "a precarious world where fact, lore and misinformation had become so intertwined that extracting a pristine truth was almost impossible". Nobody even seems to agree on what the Holy Grail is: some say it is the cup used by Jesus at the Last Supper; others that it was used to collect his blood at the crucifixion. Needless to say, the Templars haven't been too eager to clarify any of this publicly.
Then, late last year, the group apparently made an unprecedented communication with the outside world. It emerged that the Templars were demanding an official apology from the Vatican, for having persecuted them in the 14th century - and that the Vatican was giving "serious consideration" to the matter. The demand came in a letter, signed on behalf of the grand master of the Templars. And for the conspiracy theorists who have pursued the knights for centuries, it was accompanied by a tantalising clue: an address. In Hertford.
If there is something implausible in the idea that huge stretches of world history have been secretly coordinated from a market town just north of the M25 - well, maybe that's what they want you to think. The local newspaper, the Hertfordshire Mercury, certainly seems convinced: over the past few months it has published several intriguing stories quoting local Templars, who told its reporter of a secret network of tunnels under the town that was still in use by the order. "It reaches beyond well known central Hertford locations," one Templar said, "including the tourist office, the castle, Monsoon, Threshers, the post office, Bayley Hall, and the council offices." Treasures of "immense importance" were hidden there, it was claimed. Was the quest for the Holy Grail finally about to come to an end? More surprisingly still, was it about to come to an end underneath Monsoon on Market Place?
The man who has persuaded the Vatican to consider apologising, Tim Acheson, meets the Guardian in icy morning fog in Hertford, wearing smart pinstriped trousers and a thick winter overcoat. His midnight-blue sports car is parked nearby. "As you might expect," he says, setting the tone for the day, "there are going to be some things that I'm not able to discuss."
Acheson claims to trace his ancestry to a renowned Scottish Templar family of the same name, though he won't confirm his own role in the group. Might he just be a practical joker who managed to fool the Vatican? "That could well be, couldn't it?" he says, as we order coffee in a Hertford establishment closely modelled on All Bar One. "I can't tell you anything to prove that I'm not. I think that would be a perfectly reasonable theory."
There is, however, sound historical footing for the idea that a Vatican apology might be warranted. The Templars were victims of their own success: they had been granted the right to operate, during the era of the Crusades, with unprecedented freedom, levying taxes and growing rich by establishing some of Europe's first banks. (According to legend, they also invented the biscuit.) Envy and hostility ran high, until, on Friday, October 13 1307 - the original unlucky Friday the 13th - hundreds of Templars were arrested in France. They stood accused of homosexuality, of devil worship, of crimes "horrible to contemplate, terrible to hear of", in the words of King Philip of France, who ordered the arrests. They were tortured, by the Inquisition, into admitting heresy, including their scandalous belief that Jesus had had children with Mary Magdalene. Their grand master, Jacques de Molay, was burned at the stake a few years later, and the Templars were officially disbanded by the Pope.
But only officially. "The vast majority of Templars either escaped, or didn't escape, but survived," Acheson says. So how did they end up in Hertford? History records that a number of them were imprisoned in Hertford Castle, but how did Hertford become a centre of operations? "I can't really tell you that. All I can tell you - it's going to be quite vague - is that they flourished in western Europe." He explains that there is a stained-glass window in St Andrew's Church, just down the street, that contains a clear metaphorical allusion to the Holy Grail, and a cryptic hint that it might be hidden in Hertford. In the picture, Acheson adds, Jesus and Mary Magdalene are looking at each other "in a very meaningful way". (Later, I find the window, interrupting local parishioners who are decorating the church for Christmas. I think I can see what Acheson means about Jesus's expression, although mainly he just looks a bit depressed.)
Among the many things that don't quite add up about the Templars' request for an apology is: why now? Why break the silence, drawing all manner of unwanted curiosity from Grail hunters and Da Vinci Code tourists? Public accountability is a laudable goal, but it's hardly something you expect from the secret rulers of the universe. Indeed, when a group of amateur archaeologists recently announced their intention to investigate Hertford's tunnel network, someone posted a message on a local website warning that anyone who tried would be "dealt with". The message read: "Anybody intending to find out more, let alone discover hidden areas of the labyrinth, should check their life insurance policy very carefully indeed."
Acheson simply says he thinks it would be fitting for the Vatican to issue their apology in time for 2007, the 700th anniversary of the start of the Templar suppression. "Among my peers, there are people like me who believe that these issues deserve further attention ... There's a new generation coming through that strongly believes it's time to be a bit more open. I'm part of that generation." Besides, he says ominously, "Things are about to happen that will deserve attention."
The notion that "things are about to happen" recurs throughout the Templar conspiracy theories that clog up the internet. Seemingly, 2000 had been awaited as a watershed, the moment the Templars' secret knowledge would cascade into the public domain. It didn't happen, of course.
So what sort of "things" is Acheson talking about?
"I can't tell you."
OK. But could you maybe give me a rough idea of the timescale? Are these things going to happen this year? This decade? Next century? "I honestly can't tell you. I know it sounds ridiculous, but I can't tell you."
Acheson takes me on a walking tour of Hertford, and proves a knowledgeable guide, but a frustratingly cryptic one, too. So I decide to take matters into my own hands and head for Monsoon. Gemma, the manager, responds far more patiently to Grail-related inquiries than might arguably be her prerogative. There's no tunnel beneath the shop, she insists, "just the store room" - but it's "definitely haunted. When we have sales meetings there you can hear someone walking over our heads, or doing the vacuuming. But upstairs, the shop's closed and empty."
Has she ever found anything unexpected down there? Like maybe a cup, or something? "No," she says. "But there is ... the Accessorize cupboard." She leads the way through the store to the adjoining branch of Accessorize, pushing past a display stand of silky hats towards a corner cupboard. Opening it, she points to a square piece of metal resembling a manhole cover, sunk into the floor. "We don't know what's under there. But there's a strange smell." She enlists a colleague, Jo, who has worked there longer. "Have they ever looked underneath there?" Gemma asks.
"Yes," Jo replies. It would be atmospheric to be able to report, at this point, that her eyes open wide with terror, that she starts to tremble. But she doesn't. "It smelt a lot," is all she can remember.
Generally, in fact, the people of Hertford seem rather reticent on the subject of the Grail. Do they know something they're not telling? Eventually there seems nothing for it but to abandon any attempt at subtlety and ask Acheson directly.
"Tim," I say, as we walk through the fog back to his car, "do you know where the Holy Grail is?"
We stop at the kerbside to let an articulated lorry pull out. Then we cross the road, past a Mazda dealership, towards the car park.
"No," Acheson says after a while, with a thoughtful expression. "No, I'm afraid I don't."