For Nick Utechin, it was Douglas Wilmer in deerstalker and cape, in black-and-white on BBC TV. For the latest generation of Holmesians, it is Benedict Cumberbatch, in long coat and scarf, who has sparked an enthusiasm for Conan Doyle and his fictional detective Sherlock Holmes. As a child, Nick discovered that his middle name, Rathbone (his mother’s maiden name), was shared by the actor who had first created the deerstalker and cape look. Basil Rathbone’s performance in the 1939 film of The Hound Of The Baskervilles had been a cinematic benchmark for all the actors who followed.

Nick, who lives in Headington, started to read the books, buying John Murray’s illustrated editions from Blackwell’s children’s bookshop in Oxford.

He said: “I joined the Sherlock Holmes Society in 1966 when I was 14. I had discovered that I was a distant relative of Rathbone and managed to find his address and wrote to him. He died three days after I sent the letter in 1967, so he almost certainly never received it. That was part and parcel of my interest in it.”

Nick went on to a successful career as a BBC radio broadcaster and producer, but his interest continued in his spare time. He edited the Sherlock Holmes Journal and gradually added to his collection of Holmes books and ephemera. He is also a member of the (American) Baker Street Irregulars society — the expert’s expert, in fact.

He has spent a lifetime inside what Oxford detective writer Dorothy L Sayers called ‘the game’ of Sherlock Holmes (“to be played as seriously as a county cricket match at Lord’s”). Players produce academic papers about such mysteries as the elusive first name of Professor Moriarty, or asking how many wives Watson had — with not even a hint of a suggestion that these are fictional characters.

Nick’s most recent contribution to this scholarship was real, not imaginary. He finally established when the ‘game’ was first played. Before Nick’s research, it was thought that Ronald Knox first gave a talk — entitled Studies in Sherlock Holmes — to a student society at Trinity College, Oxford, called the Gryphon Club on Monday, March 13, 1911. Nick established that Knox actually gave a talk called The Mind and Art of Sherlock Holmes three days earlier, to the Bodley Club at Merton College.

Nick has co-written new stories in the style of the original, plus a book called Sherlock at Oxford, and is sought after as a proponent of the idea that Sherlock was a graduate of Oxford, rather than Cambridge.

So it comes as a surprise that he is delighted by Benedict Cumberbatch’s portrayal in the controversial BBC TV series. Surely an expert on gas lighting and hansom cabs must be dismayed by a Holmes who swaps the deerstalker for a long coat and scarf, with nicotine patches replacing the pipe? And shocked by Martin Freeman as an equally modern, technology-savvy Doctor Watson, who’s often seen blogging his diaries.

But Nick loves the series, awash with GPS, texting and on-screen graphics, saying that it proves Conan Doyle’s stories can be as relevant in the 21st century as they were in the 1890s.

“Anything that keeps the stories alive for a generation who have a lot of other things going on is wonderful. It is incredible that they are still interested in a character created 125 years ago.”

Last year marked the 125th anniversary of the publication of Conan Doyle’s first story. Holmes, loosely based on Conan Doyle’s mentor, forensic surgeon Joseph Bell, first appeared in 1887 Beeton’s Christmas Annual, in a story called A Study In Scarlet. The anniversary was marked all over the world and Nick was interviewed by, among others, Spanish newspaper El Mundo and an Australian radio station. He said: “The Sherlock Holmes Society of London alone has 1,500 members and there are other societies around the world. The interest has been phenomenal.”

Nick was approached by publishers David and Charles to produce a Sherlock Holmes book in the Amazing & Extraordinary Facts series, and his account certainly puts the recent revival into context. Despite the rather misleading title, the book is not a series of disconnected titbits, but a coherent narrative that puts the detective into the context of his original time and place, and looks at his recent reincarnations.

“Everyone thinks of fogs and hansom cabs and yet the stories were written over a span of many years,” Nick said. “He receives telegrams and even uses the telephone. The last story was written in 1927, 40 years after the first one. Conan Doyle himself kept moving with the times and each generation has a new Sherlock Holmes. “The first film was in 1900. Basil Rathbone puts his mark on the character and then everyone re-invents Holmes for a new generation. For people of my age, Douglas Wilmer was the man. He will be 93 soon. I wrote him a fan letter in 1963 and he kept it and gave it to me when we met later. “Then there was Peter Cushing, then Jeremy Brett – each one is seen by many people as the definitive Sherlock Holmes, but they played him in totally different ways.”

Nick believes the Benedict Cumberbatch series is totally in the tradition of the original – “but using it to spin modern TV stories off”. “We don’t all watch the same thing on TV any more, yet the last episode of the second series was watched by 13-14 million people. It is staggering. Everything about the original is in place, but it has been given a clever spin.

“For purists like me it is great fun. It keeps Conan Doyle’s creation at the heart of things. The relationship between Holmes and Watson is just right, with the stories being written by Watson.”

Nick’s only gripe with the series is the suggestion that the pair might be gay. “Holmes is not interested in women – that’s clear — but in Victorian times, it was common for men to share rooms together. Otherwise, it is spot-on.”

* Sherlock Holmes: Amazing & Extraordinary Facts is published by David and Charles at £9.99. Filming for the third BBC series of Sherlock starts in March.