The first contact between my bare feet and the cold, squidgy tidal mud of the Slakes brings me up short. Black, viscous, icy goo oozes up between my toes, but it's already too late to step back. Dirty feet cannot be forced back into socks and shoes, and anyway, pain – or more precisely mild discomfort – is part of what I'm here to experience.
It is Good Friday at Beal Sands on the Northumbria coast and the chill in the air is impervious to the thin, lemony mid-morning sunlight. Along with about 100 similarly unshod pilgrims, I am setting out along the ancient Pilgrims' Way across the three-and-a-half miles of shimmering silver mud flats that separate the mainland from the Holy Island of Lindisfarne. Our route is staked out by a straight line of barnacle-encrusted wooden poles that have been guiding pilgrims for 1,300 years, but the crossing is still treacherous, with quick sand and gullies, not to mention the imperative to time it right so as to beat the incoming tide that twice a day turns the Slakes back into sea. Oh, yes, and then there are the five life-sized wooden crosses we are carrying, this being the anniversary of Jesus's crucifixion.
In the pre-Reformation era, this type of hard-graft pilgrimage was commonplace, its physical demands and spiritual aims well understood by participants and observers alike, as groups trudged along the lanes, byways and coastline of Britain en route for a host of shrines, holy wells and great monasteries. After the destruction of so many of these destinations with Henry VIII's break from Rome in the 16th century, however, the tradition was first suppressed by the new austere Protestantism and then lost to indifference. All that eye-catching, self-flagellating religion was something best left to the Catholic countries of the Mediterranean, it was said, with their hair shirts, gaudy statues and wayside altars.
To neglect has been added in our own secular, sceptical times, confusion about the real point of public acts of witness like this one at Lindisfarne, organised each year by the Northern Cross group. To the uninitiated, they look suspiciously like medieval masochism – that, at least, is what is written on the faces of motorists who peer at us as they take the easier option of driving across the tidal road to Lindisfarne opened in 1966. They peer at our mud-encrusted feet, they stare at the crosses we are shouldering, and they shake their heads, turn up the car heater and get back to deciding which pub to visit on Holy Island for a Bank Holiday drink.
With all of the holy islands that lie just off our shores, there is an element of risk in getting there. Lindisfarne, only truly an island twice a day, is no different. Dicing with the tides has always been and remains an essential part of the allure – whether you are slipping and sliding in bare feet across the traditional Pilgrims' Way or motoring on the more recent road, which comes complete with elaborate warning signs depicting a Barbour-green 4x4 sinking beneath the waves having misread the tide timetable. You have always had to step beyond what is normal and comfortable to get to Lindisfarne. The quid pro quo is that by making yourself vulnerable, and, please God, surviving, you are somehow laying yourself open to seeing things in a different way when you get to this island with its history of saintly monks and miracle cures. Your guard is down.
The connection between holiness and islands is here spelt out unambiguously. "The Holy Island of Lindisfarne" reads the brown tourist road sign that directs visitors off the main A1. It is a formula first employed by pilgrims in medieval times to distinguish their destination from any another island that people might want to walk to. As with any name with more than three syllables, this ungainly formula has been subsequently abbreviated – to Holy Island or Lindisfarne, but rarely both.
Its twin names, though, still have a use if said in full because they neatly cover its history. Lindisfarne has a romantic Celtic ring, anchoring the place as a stronghold of early Christianity with charismatic itinerant monks coming here from the 630s onwards from Iona on the west coast of Scotland, cradle of the Celtic church in Britain. Holy Island, by contrast, has a more precise, what-it-says-on-the-tin, Anglo-Saxon air that reflects the subsequent success of the island's monastic community, after the landmark Synod of Whitby of 664, in following that gathering's dictates and mixing those Celtic roots with a more formal style of Roman Christianity to produce, at their priory, an unrivalled centre of scholarship, evangelisation and pilgrimage.
The most celebrated monk of all was Cuthbert, that rare thing in 21st-century Britain, a saint with popular recognition, at least in the north of England. As first prior at Lindisfarne and subsequently its bishop in the last third of the 7th century, Cuthbert was a holy man whose reputation as a preacher and healer drew crowds to "his" island. They swelled after his death in 687 because his stone coffin, containing his perfectly preserved body, was reputed to have the power to effect miraculous cures. That proved an even more powerful magnet for those who walked across these mud flats before me than the Lindisfarne Gospels, peerless late-7th-century illuminated manuscripts produced by the island's monks, and now in the British Museum. The overall effect was dazzling. Lindisfarne became, in the words of the poet and chronicler of myth and legend, Kevin Crossley-Holland, "a kind of Mecca, a Canterbury of the North, the brilliant focal point of a brilliant age".
Such splendour, however, in an isolated spot that had only tides for protection, also attracted the attention of marauding Vikings. They came in 793, their first raid on English soil. They were less interested in miracle cures than making off with the gold and silver plate given to the abbey by grateful pilgrims. They returned several more times, murdering the monks who stood in their way, and the threat they posed cast such a shadow over Lindisfarne that, in 875, Cuthbert's successors abandoned their island sanctuary, dragging carts back to the mainland loaded up with the saint's body, the head of another dead abbot, and the bones of several previous bishops, plus manuscripts and whatever plate remained.
After spells in Chester-le-Street and Ripon, Cuthbert's corpse finally found a place of greater safety in Durham ' Cathedral where it remains to this day, but the leaving of Lindisfarne had caused it to rot like all other mortal flesh.
A group of Benedictine monks from Durham did return to establish a new community on the island in 1093, and consecrated a grand new church in 1120, but the golden age could never be recaptured. The whole complex was destroyed in 1541 on the orders of Henry VIII, though a romantic ruined arch is just visible up ahead of us on the skyline.
The seasoned walkers of Northern Cross are setting a cracking pace. Last year, one explains as he hurries sure-footedly past, they were caught in a snowstorm, so they have learnt not to dawdle. I try to keep up, but – still picking where I place my feet gingerly – I fall in with those carrying the crosses.
They are remarkably uncomplaining, all the more so given that this is no one-day wonder. The walk across the Slakes is the finale of a series of week-long treks that have brought my companions, in small groups of 15 to 20, each with its own cross, from starting points around northern England and southern Scotland to Beal Sands this Good Friday morning. They try, wherever possible, to use public footpaths, but occasionally end up on busy roads, dodging traffic. Their nights have been spent on the floors of church halls in sleeping bags, with minimal bathroom facilities and only such sustenance as can be rustled up between a long day's slog and soaking your blisters. So why do it?
"It gets compelling," explains Ken Williams, one of the founder members, a jovial man in his sixties with unruly grey hair and a shocking-red sweatshirt that is studded with small white and red crosses. These are mementos, he explains, of previous Northern Crosses, red for Christ's suffering and death, and white for his resurrection. "Your feet start getting itchy around Easter time. The years I haven't done it, I found myself walking up and down the garden singing 'Avanti Populo' at the top of my voice."
Each of the week-long "legs" has its own small booklet that participants carry with daily hymns and readings – plus the odd marching song. Williams breaks into a chorus of "Avanti Populo". He gestures at me to join in, but I've never heard it before. "Don't you know it?" he asks, breaking off abruptly. "It's an Italian nationalist song. You don't hear it in churches that often, but it's great for walking."
Northern Cross started in 1976 with a group of students, most of them Christian, but looking for a different way to celebrate their faith in the build up to Easter from traditional church services. They tried a similar pilgrimage to the Marian shrine of Walsingham in Norfolk, "but we decided," Williams recalls, looking me straight in the eye, "that we wanted to walk somewhere prettier. Norfolk's very nice but very flat. When you are walking with a cross and the big event of the day is turning a corner, you need to look elsewhere. We thought of Iona, but it was too remote. And then we thought about Lindisfarne, discovered there was a hostel there, and here we are. This last part is the easy bit. In some ways, the least important." He must see my face fall because he adds hastily, "but in some ways the most important, because it is the final few miles. It's a bit like the Last Night of the Proms."
Like the Promenaders whose antics belie the traditional image of classical-music audiences, the Northern Crossers seem determined to play down any spiritual side to their endeavour and therefore the usually negative stereotype of religious believers in this age of Richard Dawkins, The God Delusion and Thought for the Day. There's much talk, as I engage different groups of walkers, of the pull of comradeship on the walk, of the joy of seeing familiar faces year after year, of stopping off at pubs on the route, but what about the unfashionable faith element?
"It's not a Holy Roller group," Jan, a writer in her fifties from Edinburgh, rebukes me. "When I tell my friends I'm going to Northern Cross, and that they do carry a cross, they say, 'Oh my God, it's like Monty Python.' The first time I came I told myself that I would make an excuse and go home, that I just couldn't walk along the road carrying a cross. Completely no. But soon after we set off, someone in my group got a big blister and I found myself thinking, 'Why am I standing outside myself watching myself do this?' I've done Carnival in Rio. There comes a moment when you stop thinking about what other people think of you, worrying that you are part of a group of Christian nutters, and realise instead that they are just a bunch of nice people walking along."
Nutter, of course, is the word Tony Blair used when explaining his decision to keep shtum about his Catholicism until he left Downing Street. He didn't want voters taking him for a "nutter".
Despite a constant turnover in my walking partners, I struggle to extract anything spiritual from them. Eventually, it dawns on me that I am being too direct, too prescriptive. This is a pilgrimage that prefers to let its crosses do the talking. Maggie Mason is another veteran, a town planner by trade, a cradle Catholic who has joined the Methodists, the mother of grown-up children, and Williams' sister-in-law. She is also chief organiser this year – an elected role decided by a ballot on Lindisfarne at the end of the previous year's event. "It's physical and it's a physical witness," she reflects when I ask her why participants are so reluctant to distinguish between what they are doing and the Ramblers' Association. "I think it is a prophetic act. Jesus did a lot of prophetic acts, like riding into Jerusalem. He did things where people could work out what he meant, but he didn't necessarily have to explain it. So we walk and we carry a cross and we develop our understanding of it as we walk and as we experience it."
The sun is starting to burn off the low cloud, giving the flats a mirror-like quality. There is, I'm relieved to note, no sign of snow, but Lindisfarne appears as far away as ever. I content myself with counting off the refuge boxes, peculiar, off-white wooden garden sheds, on stilts and with a ladder up the front. They look like a child's drawing of a treehouse, but with the tree rubbed out. In this treacherous land/seascape, they are the equivalent of static lifeboats for those cast adrift by incoming tides, a place to scramble above the waves.
"Northern Cross does recharge the spiritual batteries because it takes you away for a week from the hustle and ' bustle of normal life," another veteran, Mike Holliday, is explaining. What's the oddest reaction he's got from someone he has passed when carrying the cross? "Some people thought it might be a good idea to throw stones at us," he replies. He says it in such a light-hearted way, I don't quite take him seriously at first. You might be puzzled by the sight of grown-ups walking through the countryside with a cross. You might even feel irritated by such a naked display of Christianity if you were a convinced atheist. But stoning, with its overtones of Biblical martyrdom? "Who knows why they did it," he says. "We didn't stop to ask. But certainly they find us strange. This happened on the other side of the Scottish border, but we have also had it in Northumberland." Did the route take them close to troubled estates, I ask? He laughs at the easy assumptions I am making. "No, this was in the countryside. It has lots of kids with no notion of how to behave."
It is time for the cross-bearers to stop and exchange the burden – a regular ritual. There is a short pause to readjust the scarves tied round the central joint as padding. "It still sticks into your shoulderblade," Holliday confides, "but over the years the crosses have got lighter."
There are plenty of younger people out here on the Slakes, many of them the children of the original Northern Crossers. Franckie, newly liberated from cross-carrying, has just returned from working in the Antarctic as a meteorologist, so she knows all about endurance in tough conditions. She first came on Northern Cross with her parents. "When I got to 17 I thought, 'I'm too cool for this' and lapsed, but by my fifth or sixth year at uni, I'd come back. I don't generally go to church week by week. I just don't. It's really inconvenient on Sunday morning, but I get a top-up here."
The longer we walk, the less talking we do. It may just be conserving energy, but, curiously, the effort required to put one foot in front of the other on this treacherous surface pales the further we go. It may just be the onset of frostbite, but my awareness of my body and its aches, pains and demands recedes and the sheer monotony of walking takes over. It is, in one sense, a familiar feeling, part of any decent countryside or coastline hike, but here the presence of the crosses, the posts of the Pilgrims' Way and the ruins of Lindisfarne's priory up ahead on the horizon give a particular direction to the reflective mood that is taking me over.
The American essayist Rebecca Solnit provides a good description of what seems to be happening to me in Wanderlust, her history of walking: "Walking itself is the intentional act closest to the unwilled rhythms of the body, to breathing and the beating of the heart. It strikes a delicate balance between working and idling, being and doing. It is a bodily labour that produces nothing but thoughts, experiences, arrivals." What she so eloquently identifies, pilgrims down the ages – including this band of Northern Crossers – already know. Taking on an arduous, physical labour in the form of a long or challenging walk can help you to access a spiritual dimension shut off during the everyday routine.
But it has to be hard. No gentle stroll will suffice. The origins of the word travel – in travail, or work – suggest that it should not be the effortless cruise or the door-to-door service of holiday company brochures, but rather a sustained and purposeful effort. Christianity has had a tendency, of course, to take that effort to extremes – not only encouraging pilgrims to trek long distances in bare feet, but also for the really devout (or penitent) to put stones in their shoes or to ascend on their knees the Scala Santa, or "holy staircase" in Rome's St John Lateran Basilica. The essential point, though, remains not one of degree, but of purpose. There is a conscious effort in the travail of walking to make the spiritual tangible.
The realisation makes the second half of the walk pass rather more quickly than the first. I am almost disappointed when we make land, but warm bowls of water are awaiting us on the shores of Lindisfarne, along with our shoes, neatly arranged in pairs, thanks to volunteers who have formed a support crew. The mud is curiously reluctant to wash away. In smart urban spas, someone remarks, you would pay a fortune to have it rubbed into your toes.
A small crowd has gathered on the foreshore to watch our arrival. Since Northern Cross is not about evangelisation, there's no valedictory speech, victory lap, or even invitation to join the walk up to the ruined priory where there is to be an ecumenical service. The absence of any attempt to rope them in seems to puzzle the onlookers even more, but at least, Holliday points out, no one is throwing stones.
'The Extra Mile: A Twenty First Century Pilgrimage', by Peter Stanford, containing accounts of trips to Bardsey, Glastonbury, Holywell, Iona, Stonehenge and Walsingham among others, is published by Continuum at £16.99Reuse content