Of all the characters in fiction who have multitudinous lives off the page, Sherlock Holmes – and, as is only logical, Dr Watson – must surely take the crown. Not just films, radio and television series but additional adventures such as Conan Doyle never intended. The Granada television series starring Jeremy Brett as Holmes is generally reckoned to be the most faithful to the original concept. Jeremy Paul, who scripted several of its episodes, has written this new play about what one might describe as the spaces between Holmes’ and Watson’s adventures.

Both Peter Egan as Holmes and Philip Franks as Watson have played these roles before and they slip so comfortably into them that the stage at times seems crowded with too many shadows. Paul reminds us that Watson is an efficient army medical officer who is less at home invalided out into civilian life than he would like to think. Egan knows that part of the fascination of Holmes lies in the fact that he is a selfish and disagreeable as well as an immensely clever person and doesn’t play him for sympathy. An interesting case of bi-polar disorder?

Director Robin Herford and designer Simon Higlett sweep us into the cluttered interior of bachelors’ lodgings in late 19th century London and surround this with stairs and walkways on which menace may lurk and from which danger can descend – though I’m not quite sure if the box files are not anachronistic. There are three people about whom we hear a great deal – the opera singer Irene Adler (with whom Holmes may – or may not – have been in love), his brother Mycroft (that mandarin panjandrum of Whitehall and the Diogenes Club) and Professor Moriarty (whose devious thought processes and equally twisted actions are so much Holmes himself reflected in a slightly distorted mirror),

It’s all very clever, looks good and is well acted. But there’s a heart missing somewhere – not just in the emotions of the characters but in the play itself. It’s always said that a good biographer has to be a little in love with his or her subject – even when that subject is an unpleasant character with few, if any, redeeming virtues. Perhaps Paul is too close to the Holmes canon to be subjective. Re-reading the stories one has the feeling that their hero and his amanuensis are, to use a popular phrase, economical with the truth. And theatre – for all its illusions – does need truth to work its proper magic.