Long in tedium, short in dramatic action and inescapably circular, the M25 is not so much The Road to Hell, as Chris Rea once sang, but life itself.

On a bright spring morning, however, Britain's least loved motorway was almost beneficent on Monday when viewed from the seats of the first sell-out coach tour of the 117-mile London orbital.

The Middlesex County Asylum, Heathrow Terminal 5, South Mimms services, Badger's Mount; all these landmarks took on a pleasing sheen when subjected to the scrutiny of Nigel Pullen, the guide for the Brighton & Hove Bus and Coach Company's surprise hit day-trip.

With his strawberry blond thatch and light-reactive glasses, Pullen looked the tour-guide part and did not disappoint with his deadpan delivery of a stream of trivia that flowed as freely as the traffic.

Like estate agents or tabloid journalists, tour guides have their own peculiar argot: toilet stops are "comfort breaks", Thorpe Park's amusements are "thrill rides" while Middlesex Asylum was "now a residential development of outstanding prowess, ie, quite expensive," explained Pullen.

We joined the motorway at Godstone and climbed Reigate Hill to the dizzying heights of 220m, the most elevated spot on the orbital. "Oxygen masks will be dropping from overhead shortly," quipped Pullen. Later we passed a farm where meerkats live 20 yards from the carriageway. "They would be out to sell insurance if we were stuck in a queue," he observed.

After lunch at South Mimms, one of three service areas on the motorway, Pullen was surprised to still have a full coach. Some punters were just surprised to be there.

"I'm speechless and I don't think that's ever happened," said Julie Hayes, 45, taken on the £15 tour as a surprise by her boyfriend, James Smith. "What have I learned?" mused Hayes. "Never to go out with a man from south London."

Working as a gas engineer in south London, Smith knew a thing or two about traffic jams and was fascinated by roads. "It's a random thing, it's abstract, it's eccentric. People have different interests. How do you quantify normality?"

And so we learned about the man logging every set of concrete steps on motorway edges around the country and the meaning of those enigmatic blue signs with M25 and a random number on them, which give the distance in kilometres from the Dartford tunnel for the emergency services.

Like life, the M25 seduces you with its banality before subjecting you to occasional dystopian extremes. Severe weather on the nation's biggest car park in 2010 caused the Red Cross to provide blankets and tea for motorists stranded in their cars for 17 hours.

Death is also always just around the corner, from the adverts for prostate cancer awareness above the urinals in the services to the coach's own warnings about the risk of deep-vein thrombosis (hence two comfort breaks).

Just as we entered Buckinghamshire – one of six counties the motorway passes – Pullen gave an intake of breath. "This is what we've been waiting for — an incident, folks," he declared as dot-matrix signs ordered us to slow to 50mph.

"Let's see if there are bodies!" cried one passenger.

It was nothing – just a lorry on the hard shoulder.

There were several coach tours of the M25 in the 1980s and perhaps it is no coincidence that the 2012 version has proved so popular. The M25 was opened by Margaret Thatcher in 1986 and will endure as a monument to her era far longer than wars or broken unions. A visible symbol of individualism and the triumph of the car, the motorway was widened by the Blair government, building on the Iron Lady's legacy in every way.

All human life was here, including the only Taco Bell restaurant in Britain and the Dartford bridge (designed by a German and opened by the Queen). There was wildlife too: five buzzards, two kestrels, a sparrowhawk and at least 100 plastic bags fluttering in trees. Clacket Lane services is "quite good for rats", pointed out Mark Weston, who works for the RSPB and was assessing whether the coach tour would interest his members.

As we completed our road to nowhere, applause broke out. "Please tell other people," implored Pullen. "Now I've got this far in my research I want to do it every week. Is that all right, Graham?" The driver shuddered. "Find another driver," he growled.