Her laptop sits on the desk, carefully positioned so the bookcases fall symmetrically behind her when she does a video conference. It’s a fancy model with a rose-gold cover. Far prettier than the boring black model I have for work. I cross my fingers as I lift the lid and it blinks into life.

Couldn’t find you. The message on the screen blinks in time with the little red light of the camera. Move closer to the camera. Couldn’t find you. I begin to panic. I need to get into her laptop. How can the camera not think I am her? I know that facial recognition is flawed for twins. I had a client once who made a huge deal of me being a twin and insisted I had tri-factor security installed on my work laptop so it really was only me who could use it. Retina, fingerprint and facial recognition. We took it off when the commission ended though; far too much hassle and too prone to glitching.

As my panic mounts, I begin to gurn. Twisting and contorting my face in an effort for it to recognize me. I see my reflection in the laptop screen and pull myself up. No way would Leah pull faces to unlock this thing in public. Deep breath. Then I turn my body forty-five degrees, push my chin up, widen my eyes, allow a glimmer of a smile to tug at the corner of my lips. Leah’s press pose. The screen unlocks immediately. I’m in.

Her desktop is perfectly ordered, another curated piece of her flawless public life. A picture of the two of us from when we were little forms the background. I thought they had used this picture on the front cover of the book, and tried to sue for the use of my image without my permission. But it turned out that the publisher had got round it by carefully knitting together two pictures of Leah so it merely looked like both of us. I’d received a letter from her lawyer that Leah had very obviously dictated and insisted they send:

As you will see, this image does not contain your specific likeness. While we apologize profusely for the similarities you bear to our client, these similarities are insufficient to warrant grounds of restricting the image of our client. Restrictions of this nature would be tantamount to not allowing Billie Piper to be photographed on the red carpet because Sandra from Wigan bears a passing resemblance to her. You will understand the farcicality of this kind of request.

Leah had chosen Billie Piper on purpose. I always said I wanted her to play us if there was ever a movie made about our lives. When we were writing the original first draft of the book, we’d spent a lot of the time watching reruns of Doctor Who in the evenings and drinking the cheapest wine known to man.

My first job is to order a new phone. Leah’s is lying at the bottom of the lake, underneath the decking. I nearly have an issue when the lady on the help desk asks for Mum’s maiden name and my answer doesn’t match what she has on file.