When Guy Ritchie announced he was planning a film featuring Britain’s most famous detective and starring an American as Sherlock Holmes, many purists may have choked on their own opium pipes.

 Fear not. Although Sherlock Holmes takes an undoubtedly modern spin on Conan Doyle’s sleuth, it is Ritchie’s most accessible film. Being sent back to the Victorian era has forced the director out of his world of well monikored cockney geezers. What remains is some kinetic camerawork and a fantastic central pair of performances, even if there isn’t a deerstalker in sight.

Holmes’ (Robert Downey Jr) intelligence is tested to the limit when the last man he arrested, Lord Blackwood (a menacing Mark Strong) manages to survive a trip to the gallows and starts bumping of people in supernatural manners. Roping in his faithful assistant Watson (Jude Law) and ex flame and conwoman (Rachel McAdams), Holmes must unlock the mystery while battling some heavies who seen leftover from Ritchie’s Snatch.

Central to the film is the relationship between Holmes and Watson with Downey Jr and Law arguing throughout like Statler and Waldorf, with Holmes trying to scupper Watson’s impending marriage. Although Conan Doyle may never have envisaged his sleuth as a fighter, this Holmes is analytical even when he fights in the ring, analysing how he will disable his huge opponent. Not quite a troubled genius, he needs Watson to keep him from alienating everyone he comes into contact with.

The comedy dynamic is often more important than the plot, but importantly the film does have a cohesive story that makes narrative sense. At over two hours, it overstays its welcome a little towards the end but is sewn up neatly while still leaving plenty of scope for a sequel.

Just tell one hint for Mr Ritchie if he uses Tower Bridge as a location again. It is nowhere near the Houses of Parliament!