This article first appears in Vol. 24: Slow.

On On a gentle ascent by Tolsford Hill, butterflies dance between hawthorn blossoms. The Kentish breeze liberates crumbs from my half-eaten sandwich. Dewy grass caresses my bare feet. Squinting, I can see France on the horizon.

"Travel is like Star Trek." I turn to my picnicking companion, William Parsons. Almost choreographed, he thrusts his hazel- wood staff back and forth, relaying his emotion. "Our cars, trains and planes are teleportation devices that allow us to disappear from the map," he continues. "All reality traditionally encountered between places is airbrushed into same-same grey tarmac. Our dream is one of pure destination."

We're shy of four miles into a three-day pilgrimage to Canterbury and behind schedule, though William is unruffled. I check my watch again, not yet accustomed to the pilgrim's pace. Earlier that day I had met William and his dog, Holly, at Sandling Station. He's a classy riff on Huckleberry Finn, albeit with a fancy camera. Having spent a decade as a wandering minstrel, he co-founded the British Pilgrimage Trust with Guy Hayward in 2014.

Across the world pilgrimage is an ancient practice that is often entwined with religion. Last year over 300,000 Christians walked the Camino de Santiago across northwestern Spain, some 40 million Muslims travelled to central Iraq to observe Arba'een and over 100 million Hindus bathed in the sacred Ganges for Kumbh Mela. Britain's relationship with pilgrimage is patchier. Such routes formed a vast network in the country up until 1538 when Henry VIII banned the tradition during the Reformation.

Now the British Pilgrimage Trust is performing something of a resurrection by attempting to open up the practice to everyone from the religiously devout to committed atheists.

Over three days we walk the latter part of The Old Way, a 250-mile trail from Southampton to Canterbury taken from the 14th-century Gough map, the oldest surviving map of Britain. My history-loving heart flutters as I learn we're tracing the path the four knights took to murder Thomas Becket, Archbishop of Canterbury, in 1170.

To begin we slip down a covert footpath at the back of Sandling Station, taking a moment to appreciate the transition from tarmac to grass. It feels momentous. For the next three days my encounters with modernity will be fleeting. Within a few steps I have acquired a staff of my own, kindly sawn and secreted in a hedgerow by the British Pilgrimage Trust. It's my earthing connector and the hallmark of any self-respecting pilgrim.

Our first major stop is the 11th-century Saltwood Castle, home of the late politician and diarist Alan Clark, where his widow, Jane, graciously shows us around. It's a bizarre early interlude to our journey in which I encounter some of the family's private art collection - think Rodin and Henry Moore - pet tortoises and touch Kenneth Clark's handwritten manuscript of Civilisation. Back on the pilgrim's path, we are guided by the geography of faith. Navigating the bridleways, footpaths and hollow tracks of old Britain, our route joins the dots between underused churches, cathedrals, river sources and holy wells.

We meander through chocolate-box villages with lyrical names like Lyminge, Elham, Bishopsbourne and Fordwich. On Tolsford Hill we rest our foreheads on Bronze Age burial mounds and across the Barham Downs we visit Old England's Hole, where the Britons made their last stand against Caesar's legion in 54 BC. William regularly breaks into song. Under one especially acoustic bridge I join in, surprising myself at this newfound freedom. Along the way our staffs make useful tools for thrashing nettles and brambles, propping us up across rickety stiles and helping us scramble over a barbed-wire fence when some cows get a little too interested. Tracing the River Nailbourne I become ever more aware of nature as a refreshing and rejuvenating tonic. The wind conducts an orchestra of leaves, dappled sunlight dances through branches and I stop to smell hedgerow lilacs, dog roses and elderflower. We cross coppiced woodland, orchards and fields of roaming livestock - "Warning: sheep grazing" cautions one foreboding sign. After gathering herbs in a flask to make "pilgrim's tea", we clamber inside a hollow ash and swing from an ancient beech. In Bedlam Wood, surrounded by wild orchids, we scramble through a split branch in what William calls a "rebirthing" ceremony.

The scars of humanity seem all the more incongruous after days spent on its periphery. We pass a humming field of solar panels and several mounds of fly-tipping. Of the rivers we cross, the steely surge of the M20 thunders the loudest. Water, the source of life, is a recurrent theme. We throw pieces of silver in holy wells, drink water directly from streams, roll up our trousers and get knee-deep in an ancient pond. For a brief spell, dark clouds bruise the sky so we dance across an open field in the rain. "Water flows, life is given" choruses William, "rises from earth, falls from heaven." He isn't averse to lifting a manhole cover to get a peek of Adam's ale, nor dousing his face with holy water from a roadside drain in Canterbury.

Yet what punctuates our journey most is churches. We circumambulate each one - a practice drawing upon Buddhist, Islamic and Catholic influences - pressing our palms against the eastern wall. Venturing inside, I'm unsure whether my feelings are of veneration or mere contemplation. I read stones, admire tiles, lie down, close my eyes and bathe in the colour streaming through stained-glass windows. I can't help but feel like an impostor. However, William reminds me that holiness needn't be wrapped up in religion. The word itself derives from the Old English word halig, meaning whole. It's for this reason that the British Pilgrimage Trust has a BYOB policy - Bring Your Own Beliefs. Holy places are places toward which you feel compelled to walk. It is up to you what they are and how you engage with them, whether that be the relatives of 9/11 victims seeking solace at Ground Zero or Elvis disciples on a crusade to Graceland.

Far from being divisive, pilgrimage can be a universal experience. Travelling for growth and change in search of a place or even a state of being is something that can be shared across cultural, religious and economic boundaries. Paradoxically, while the object a pilgrim searches for can vary wildly, it's their transformative effect that connects them.

Institutionalised religion may be ebbing from British shores but there's a renewed hunger for spirituality that has, and I think will continue, to swell the popularity of pilgrimage. There's no abstract theology to get your mind around, just a willingness to make the body do what the soul desires. Sometimes I realise William and I have been walking in silence for half an hour or more, yet it's not uncomfortable. The countryside has become a canvas for my thoughts. Walking is a prayer, the rhythm of my footsteps a form of meditation.

I never did experience a jolt of clarity on my pilgrimage, though perhaps I had a quiet epiphany instead. In a world where time is money, pilgrimage is among the most extravagant forms of travel and yet also the greenest - it took me three days to saunter what I could have driven in 45 minutes.

Today we worship the god of connectivity. We set our thermostat from our phones, check our bank accounts from our watches and are increasingly disconnected from the land. We eat asparagus in winter, soar across continents watching films and steer our cars via sat nav. On a pilgrimage, however, unplugged from the digital world, we have time to think, reflect, pray and meditate. Travelling by foot forces us to slow down and honours our destination in a way that no plane or car can.

Little, it seems, has changed since Thoreau's 1861 treatise on walking. "No wealth can buy the requisite leisure, freedom and independence which are the capital in this profession," he wrote. "It requires a direct dispensation from heaven to become a walker." We arrive at Canterbury in time for evensong and the strains of the choir echo across the cathedral. By some stroke of fate I end up sitting in the Bishop of Dover's seat and place my well-trodden staff in the stand intended for his crosier - a fitting epitaph to a distinctly divine experience.