"Believe me when I say that I care for you most sincerely, but mine is not a romantic attachment. I do not love you, Watson, in the way that that word is commonly understood. And although a sexual element to our relationship might bring both gratification and convenience, I believe it would ultimately be detrimental to our partnership, our productivity.

"I am truly sorry if this causes you any distress -"

"Are you talking to yourself?"

I jump.

A presence behind me, a shadow cast in the light from the hallway. A faint waft of Guerlain - Mitsouko, her favourite.

"Watson! I didn't hear you come in." I genuinely didn't. I was engrossed, mortifyingly so. How long has she been standing there?

"I've been standing here five minutes." She is soft spoken, almost always. But the low timbre of her voice carries as far as any more strident tone. And her tone now is wry.

"Ah." Rapid thought. Recollection of oft-rehearsed refusal of Watson's imagined romantic advances. Did I use her name? Yes. Drat. An excuse is required - none immediately presents itself.

"Were you pretending to - turn me down?" She steps into the dim warmth of the living room. I check her body language - no need to disguise this action, she knows I do it. So: arms loose at sides (no accusation), jaw in normal range of half-clench-to-clench (no special tension, just the decades-old habit from a high stress job), feet set at shoulder-width apart (a challenge, but well within the parameters of our daily banter.) She wears an air of piqued curiosity, and displays no sign of hurt. There is a possible layer of amusement in her voice, but with her expression she is doing her Mona Lisa thing: impossible to read. I am increasingly certain that this opaque expression is deliberate and controlled - some (vain) attempt to wrest back her personal privacy.

Think.

"You formed a mere convenient object for a poorly remembered speech heard on a radio programme some time back. It contained elements pertinent to a case." Highly implausible but, being me, the more probable for all that.

"Oh, what are you working on?" Her heels clack on our wood floor. She has been out for dinner, at a tapas place which overdoes the garlic, with girlfriends, - no overt make up, hair loose- including one woman who has a young baby - no mistaking the floral-chemical stench of the nappy bag. "Is it a new case?"

The mysterious case of my embarrassing fixation with Watson and a fantasised rejection. Give airy wave. "Nothing of note, and now I have thought of that speech, it's clear there was nothing in it."

She stands, her hair a fall of black untouched by firelight, her eyes steady. I remain seated in the pink wing chair, and maintain my mild expression. Watson can read me too, on a good day. She frowns at me. "Ok. Good. You know, Sherlock - "

She comes close to my fireside chair, obliging me to look up at her. I am, I realise, lit by the flames; she is silhouetted, her features in near darkness.

She hesitates. Surely she is not going to use this as an opportunity to discuss the - unusual, fond, equal, professional, intimate, awkward - nature of our relationship?

She is. "You don't need to worry about having to let me down," she says quietly. "It will never happen."

"I know," I say. Do I, though?

She smiles. "You want some tea?"

"Yes. Thank you."

She goes to the kitchen and I hear the kettle clang onto the stove before I realise that her statement, and my response, could be taken several ways.

Hmn.

I am still contemplating meanings when the phone rings. Watson answers, and comes up to the library holding out the handset. "He's British. And he says he's your cousin."