And so Richard Elloway set off from Land's End, armed only with his national bus pass, a comfy fleece and plenty of timetables. On one local bus after another, he slowly trundled his way up Britain. At moments, the explorer's spirit quailed: he was horribly stranded in Tiverton, after missing the last bus to Wellington. The natives of Lincoln were restless, and rather noisy. And yet he never lost hope, or belief in his quest.

After eight days. 1,133 miles and 40 buses, Mr Elloway finally reached John o' Groats, having become the first person in history to get from one end of this country to the other by travelling entirely on local buses, for free.

Why? Why would a retired teacher of 61 leave home and hearth to hack his way through the forbidding jungle that is the British bus system? For the same reason that British men and women have always plunged into uncharted and unlikely territory: because it's there.

I found myself moved and uplifted by Mr Elloway's epic journey. His slow omnibus odyssey was somehow reminiscent of Dr Livingstone, riding his ox through the wilderness wearing that bus conductor's cap. Livingstone was the first European to see Victoria Falls; Mr Elloway enjoyed “getting off the bus and finding people's accent had changed”. They would have recognised one other as kindred spirits.

No other people on Earth do things like this. The round-Britain windsurfer, the naked hiker, the Munro-bagger, the explorer attempting to spend a night on every Hebridean island, the man who rowed his antique Thomas Crapper bath across the Channel: these are a strictly British species. The “because-it's-there gene” is hardwired into the national DNA, alongside the genes for collecting and cataloguing: this is where the spirit of Captain Scott meets the quiet obsession of the trainspotter.

None but a Briton would set out to conquer the bus system in this way, because none but a Briton would feel impelled to try. Every country has its explorers, but no other country, I believe, is almost entirely composed of secret explorers, each just waiting for the right challenge, however small, however eccentric.

I know a man who, as a student, travelled on every bus route in Birmingham. Anyone who has successfully scaled a personal summit would recognise his description of the elation, and the gentle disappointment, when he got off the last bus, on the very last route.

Success is not a necessary part of the great British quest. Indeed, we love heroic failure more: Mark Boyle, who recently set off on a two-year mission to walk to India without money, but only got as far as Calais; James Cracknell, the Olympic rower who sank two minutes after starting a 1,400-mile journey to North Africa; Captain Scott writing with frozen fingers: “We are in a very tight corner, and I have doubts of pulling through.”

The modern quest-seeker is often a charity fundraiser, a record chaser or a self-publicist, but some of the most extraordinary explorers have been private people, driven only by a particular interest and peculiarly British sort of madness.

At the start of the 19th century, the Rev Joseph Wolff, one of the oddest explorers this country has ever produced, announced that he was heading into the wilds of Central Asia to find the Lost Tribes of Israel. For many years, dressed in full canonical garb, he harangued Afghans, Sikhs, Turks, Indians and Uzbeks, trying, and failing, to convince them of the superiority of the Anglican faith. Many of his hearers did not take kindly to this. Wolff was beaten, stripped, threatened with death in a variety of complicated ways and thrown into a bug pit by the Emir of Bokhara. After completing his travels, he retired to a vicarage in Somerset and never did anything remotely interesting again.

With so much of the world already discovered, mapped and accessible via Google Earth, the “it” in “because it's there” has changed dramatically over the past 50 years. It may still be Everest, though the mountain is now horribly crowded, but it may also be a trans-island bus journey, or the Pennine Way, or the marathon, or even simply following a single sports team to every fixture.

This longing for a personal quest, embedded in the British soul, is partly cultural, a remnant from the days of empire when great swaths of the world remained mysterious, awaiting only an Englishman in a pith helmet to be “discovered”. Alongside the names of Livingstone, Speke or Thesiger, came hundreds of unknown, middle-class British explorers: missionaries, scientists, soldiers, but also many who were simply up for a challenge.

When George Leigh-Mallory declared “Because it's there!” in response to the question he had been asked so many times before, he was not intending to frame some profound truth, but stating the blindingly obvious. Everest may be a larger challenge than most, but to Mallory it was only logical that if there was a big mountain, a British mountaineer would want to climb it.

The British urge to get away and achieve some self-made mission is, of course, mirrored by the desire to come home: in the words of T.S. Eliot “to arrive where we started, and know the place for the first time”. Ernest Shackleton wrote that “no one who has not spent a period of his life in those stark and sullen solitudes of that sentinel the Pole will understand fully what trees and flowers, sun-flecked turf and running streams mean to the soul of man”.

After his solo odyssey through countless sullen bus stations, Mr Elloway must have felt the same. Why would a lone pensioner test the limits of human endurance by bus? Because it's there. Except when it's late.

Times Recommends

• Police beg us for food. What hope is there?
• Moral darkness that engulfed Baby P
• More to Advent than cheap chocolate