From an interview with AbeBooks:
Why did the story of George Edjali and his court case fascinate you and end up as the focal point of Arthur and George?
Well, it seemed a) a very unusual story (the animal mutilation, the miscarriage of justice, the racial aspect); and b) something that could still happen today, with very few changes. I assumed, when I read about it, that someone must have done a book on the case in the 100 years since it happened. But no one had – so partly I wrote the book so as to have something to read about the case.
What interests you more – the fictional character of Sherlock Holmes, or his creator, Arthur Conan Doyle?
Oh, Doyle – though the truth is that the case itself is what fascinated me, and Doyle came attached to the case, so there was no avoiding him. If it had been another writer – Kipling, say – or a sportsman, or a dentist, I would probably have been just as happy. But that said, I came to admire Doyle during the writing of the book – although (or perhaps because) he is in many respects the opposite of what I am as a writer.
Why is there an enduring fascination for so many people with both Holmes and Conan Doyle?
Though Doyle was not a great writer (as he would have been the first to admit) he was a very skilled professional novelist who created in Holmes a fictional archetype who still feeds something readers need. It is a fantasy, of course, but a compelling one: that a highly intelligent man, by pure deductive thought, a little cocaine and violin-playing, can rationally solve the most fiendish crimes which baffle the police. Fantasy, as I say, but compelling.