"so, mrs. brandon." dave sharpness has squeezed himself behind his desk and is addressing me hoarsely. "first, let me introduce myself. i had thirty years in the motor trade before turning to private investigation. having had various painful experiences myself, i know all too well the trauma you are undergoing right now." he leans forward, his chins wobbling. "be assured, i am one hundred and fifty percent committed to providing results for you."

"right. fab." i swallow. "um...i was wondering. could you not have my box file out on show, please? anyone might see it on that shelf!"

"these are dummies with false names, mrs. brandon," dave sharpness says, gesturing at the shelf. "please don't worry. your file will be safely concealed in our client secure storage facility."

"oh, i see," i say, feeling a bit more reassured. "client secure storage facility" sounds pretty good. like some underground system with coded locks and infrared laser beams criss-crossing each other. "so...what does that consist of, exactly?"

"it's a filing cabinet in the back office." he wipes his glowing face with a handkerchief. "locked every night by wendy, our office manager. now, to business." he pulls a pad of foolscap toward him. "let's start at the beginning. you have concerns about your husband. you think he's cheating on you."

i have a sudden urge to cry out "no! luke would never cheat on me!" and get up and run away.

but that would slightly defeat the point of coming here.

"i...don't know," i force myself to say. "maybe. we've been married for a year and everything seemed great. but there's this...woman. venetia carter. they had a relationship in the past, and now she's come to london. he's seeing a lot of her, and he's all distant and snappy with me, and they send texts to each other in this code, and last night he..." i break off, breathing hard. "anyway, i just want to find out what's going on."

"of course you do," says dave sharpness, scribbling. "why should you have to put up with the uncertainty and pain anymore?"

"exactly." i nod.

"you want answers. your instincts are telling you something's wrong, but you can't put your finger on it."

"that's it!" god, he totally understands.

"all you want is photographic proof of the illicit affair."

"i...er..." i'm halted. i hadn't really thought about photographic proof. all i'd thought about was getting a yes or no answer.

"or video." dave sharpness looks up. "we can put all the evidence on dvd for you."

"dvd?" i echo, shocked. maybe i haven't thought this plan through. am i really going to hire someone to tail luke with a video camera? what if he found out?

"couldn't you just tell me if he's having an affair or not?" i suggest. "without taking any pictures or video?"

dave sharpness raises his eyebrows. "mrs. brandon, believe me. when we uncover the proof, you're going to want to see it with your own eyes."

"you mean...if you discover any proof. i've probably got it all wrong! it's probably all perfectly..." i trail off at his expression.

"first rule of matrimonial investigation," he says with a lugubrious smile. "the ladies very rarely get it wrong. feminine intuition, you see."

this guy is an expert. he should know.

"so you think..." i lick my suddenly dry lips. "do you really think..."

"i don't think," says dave sharpness with a small flourish. "i discover. whether it's one lady he's dallying with, or two, or a whole string of them, myself and my operatives will find out and furnish you with whatever proof you need."

"he's not dallying with a whole string of ladies!" i say in horror. "i know he isn't! it's just this one specific woman, venetia carter-" i stop as dave sharpness lifts a reproving finger.

"let's find that out, shall we? now, i'll need as much information as you can give me. all the women he knows - both his friends and yours. all the places he frequents, all his habits. i like to do a thorough job, mrs. brandon. i will produce a full dossier on your husband's life, plus background on any women or other persons deemed to be relevant. there is nothing you will not know by the end of my investigation."

"look." i try to keep my patience. "i know everything about luke already. except for this one tiny thing. he's my husband."