THE heads start turning as soon as they enter Heathrow airport.

About 70 well-to-do men and women, mostly in their 50s and 60s, immaculately dressed in exquisite Victorian garb. Only the occasional bottle of Buxton water or copy of the Daily Telegraph suggest they’re not from another era – even their luggage is of the period.

There’s a doctor and an Indian manservant, a cardinal and a copper. There’s a rather sinister looking man in dark glasses, a landlady (though definitely not a housekeeper) and even Queen Victoria. And there’s even someone who turns out to be the King of Bohemia.

The well-read among you will have already worked out what’s going on from this handful of clues. But it’s the man at the head of the pack who really reveals this mystery.

Dressed in green tweed, sporting a deerstalker hat, magnifying glass and pipe, it can only be one person – the world’s greatest detective. For this is the Sherlock Holmes Society, and they are on a pilgrimage to Switzerland.

Worldwide the group has dozens of branches and more than 1,000 members. While most of this year’s pilgrims are from England, a number are from France, Germany, America and even Japan.

The society regularly meets for dinners and speeches, and to pore over the minutiae of Arthur Conan Doyle’s greatest creation. But for only the seventh time since 1968, they have packed their bags and headed off on a week-long trip to trace the final steps of their fictional hero.

For those not familiar with Holmes, he was originally supposed to meet his death at the Reichenbach Falls, near Meiringen, after a fatal duel with his arch nemesis Professor James Moriarty.

Public demand put paid to this and Conan Doyle eventually brought him back from the dead for a further series of adventures. But of all the stories in the canon, it’s the battle at Reichenbach that has lingered in popular memory.

To pay homage, the Sherlockians each get to play a character for the duration of the trip. They travel to a number of key locations, including the falls themselves, the quintessentially Swiss town of Interlaken and the Jungfrau mountain in the Bernese Alps, nicknamed “the top of Europe”.

They re-enact scenes from the books, enjoy lavish dinners in full evening wear and generally have a bit of knees-up. But who are these people, and what drives them to such delightfully eccentric behaviour?

It turns out a least two of this year’s group are from right here in Oxfordshire. Interviewing them proves to be a somewhat surreal experience, as many pilgrims dip in and out of character as the mood takes them.

Jeremy Burnett Rae will be a familiar name to many in the county. The South Moreton resident is a former barrister who last year protested against the closure of Didcot Magistrates’ Court. He also set up the charity Oxccarts, the Oxfordshire Community Conservation and Rural Trusts.

This is his first pilgrimage and the former Oxford University student portrays Colonel Carruthers, a blustering blow-hard straight out of the Empire. Like many in the society, it is Holmes’s brilliance that appeals to Mr Burnett Rae.

He said: “Some of the logic was a little dubious but such inconsistencies delight the society. This is my first pilgrimage. It’s terrific, demanding but a continuous booze-up as there’s a compulsory glass of wine at every stop.”

While in the stories he sides with Moriarty, in reality the men that play the two parts have a storied rivalry.

For Peter Horrocks, a fellow lawyer, is that most awful of things – a Cambridge man. As Moriarty he periodically turns up during group photos to explain his dastardly deeds. Met with the boos and hisses of a pantomime wherever he goes, it gives the bizarre feeling of being in a living play.

Sherlock Holmes has undergone something of a pop culture renaissance in recent years, what with Steven Moffat’s rather brilliant TV series and Guy Ritchie’s rather dreadful films.

One thing unites the Sherlockians though – they love the BBC series. It has certainly opened up a new audience for them.

Gwyneth Hanson, of Littlemore, is also an Oxford University graduate who now works as a gardener for Merton College. She plays Alice Turner, whose friend is accused of murdering her father until Holmes solves the case. In her 30s, she is one of the younger members of this year’s pilgrimage.

She says the new TV series helped her friends understand her rather unusual hobby a little bit more.

She said: “I am a huge fan of Sherlock Holmes, I was 15 years old when I joined the society. On this pilgrimage I have started putting names to faces, it’s lovely to see the characters come to life.”

Anyone attending the trip in the hope of spying a strapping Benedict Cumberbatch will come away disappointed though. To be fair to the pilgrims they are mostly hovering around retirement age. Most had impressive careers in well paid, professional jobs, and given the number of wardrobe changes throughout the week it doesn’t appear that this a cheap business.

But, of course, there’s plenty more to Switzerland than the tourist board’s embracing of the Sherlock trail.

Every step of the trip is laid out against the most gorgeous, sweeping vistas, with alpine lodges and mountain ranges in the background.

The Reichenbach Falls is visited via a wonderfully creaky cog railway.

But most impressive of all is the Jungfrau mountain, more than 4,000m above sea level.

It is reached by the Jungfrau Railway, which this year celebrates its centenary. While far from cheap, the mountainous train ride is spectacular.

Viewed from afar, it’s easy to come to the conclusion there is more to the Sherlockians than meets the eye.

At times it all seems a little too secret society, and with all the Union Jack waving it’s all terribly, terribly British. But individually they are all rather charming, and utterly self deprecating about their rather unusual activities. And it’s hard to be too cynical, simply because of the joy they give everyone they pass by.

There isn’t a train platform full of heads that does not turn when these scores of Victorian eccentrics turn up. Children gaze in wonder, tourists take pictures and more than once they simply receive a round of applause for all the effort they have clearly gone to.

After all, silliness on this scale simply has to be celebrated.

  • For more information on Switzerland visit MySwitzerland.com, call International freephone 00800 100 200 30 or email info.uk@myswitzerland.com
  • For details of packages, trains and air tickets email sales@stc.co.uk
  • Swiss offers 35 daily flights from London Heathrow, London City, Birmingham and Manchester to either Zurich, Geneva or Basle. Fares start from £79 return, including all airport taxes. For reservations call 0845 601 0956 or visit swiss.com
  • For more on the Sherlock Holmes Society, go to sherlock-holmes.org.uk